THE JOURNAL OF EXPERIMENTAL ZOOLOGY EDITED BY Frank William E Castle R Lillie University of Chicago Harvard University Edwin G Jacques Loeb Conklin Rockefeller Institute Princeton University Thomas H Morgan Charles B Davenport Columbia University Carnegie Institution George H Parker Horace Jatnb The Wistar Herbeht S Harvard University Institute Edmund Jennings B Wilson, Columbia University Johns Hopkins University and Ross G Harrison, Yale University Managing Edilor VOLUINIE 11 1911 THE WISTAR INSTITUTE OF ANATOMY AND BIOLOGY PHILADELPHIA, PA GIL V ( j ccud.2 CONTENTS 1911 No H JULY Jennings Assortative mating, variability and inheritance of the conjugation of Paramecium Si.xteen figures S size, in L Woodruff and George A Baitsell The reproduction of Paraemecium aurelia in a 'con.stant' culture medium of beef extract LoRANDE Two figures 135 No Ruth B Rowland gelidus AUGUST Migration of retinal pigment in eyes of Branchipu.s 143 Tlie development and function of voluntary and cardiac muscle in embryos without nerves No Fifteen figures 159 OCTOBER Studies on the dynamics of morphogenesis and inheritance in experimental reproduction II Physiological dominance of anterior over posterior regions in the regulation of Planaria dorotocephala M Child Twenty-one C tlie Four figures Davenport Hooker C 20 187 figures M Child Studies on the dynamics of morphogenesis and inheritance in experimental reproduction III The formation of new zooids in Plana221 ria and other forms Thirty-six figures H V Wilson On the behavior of the dissociated cells in Hydroids, Alcyo- naria and Asterias Thirty figures iii 281 CONTENTS IV No NOVEMBER 20 LoRANDE Loss WooDRUFF AND George ALFRED Baitsell reproductive activity of Infusoria G H Parker and H M Parshley to moist surfaces T in the The reactions of earthworms 339 to dry and , 301 An attempt to analyze the constitution of the chromosomes on the basis of sex-limited inheritance in Drosophila One colored plate H.Morgan (four figures) E Rhythms Thirteen charts 365 Lund On the structure, physiology and use of photogenic organs, with special reference to the Lampyridae Nine figures 415 J Stewart Paton E.xperiments on developing chicken's eggs 469 INDEX A LCYONARiA and On Asterias, the behavior of the dissociated cells in hydroitis 281 Asterias, On the behavior of the dissociated A., L L WooDRrFF cells In Eggs, Experiments on developing chickens, 469 Eyes and TJooKER, Davenport The development and medium of beef extract, 135 L Woodruff and Rhythms in 'constant' culture the reproductive activity of Infusoria, 339 Beef extract, The medium 'constant' culture in a lia reproduction of Paramaecium aure- Branchipus gelidus Migration the eyes of retinal of, of Branchipus gelidus, Migration of retinal pigment in the, 143 The reproduction of Paramaecium aurelia in a Bajtsell, G A., L The reactions of, 361 hydroids, Alcyonaria and, 281 "Daitsell, G TL^ ARTHWOR.MS to dry and to moist surfaces 135 pigment function of voluntary and cardiac muscle in embryos without HowLAND, Ruth B nerves, 159 Migration of retinal pigment in the eyes of Branchipus gelidus, 143 Hydroids, Alcyonaria and Asterias, On the behavior In of the dissociated cells in, 281 of, 143 in embryos without nerves The development and function of voluntary and, I^ARDIAC muscle 159 Cells in hydroids, Alcyonaria and Asterias, On behavior of the dissociated, 281 Chickens' eggs, Experiments on developing, the Infusoria, Rhythms * of in the reproductive activity 339 Inheritance In Drosophlla, An attempt to analyse the constitution of the chromosomes on the basis of sex-limited, 365 469 Child, C M Studies on the dynamics of morphoand Inheritance in experimental reproduction II Physiological dominance of angenesis terior over posterior regions In the regulation Inheritance in experimental reproduction Studies on the dynamics of morphogenesis and, 187, 221 Inheritance of size in the conjugation of Paramecium, Assortative mating, variability and of Planaria dorotocephala, 187 III The formation of new zooids In Planaria and other forms, 221 Chromosomes on the basis of sex-limited inheritance in Drosophlla An attempt to analyse the con- Iexnings, H S Assortative mating, variability and Inheritance of size In the conjugation of Paramecium, stitution of the, 365 Conjugation of variability Culture of Paramecium, Assortative mating, and inheritance of size In the, medium of beef extract Paramaecium The reproduc ion aurelia in a 'constant,' 135 T AMPYHiDAE, On the structure, physiology and use of photogenic organs, with special reference to the, 415 LcND, E T~\oMiNANCE over posterior regions in the regulation of Planaria dorotocephala II of anterior J On the structure, physiology and use of photogenic organs, with special reference to the Lampyrldae, 415 Physiological 187 Drosophlla of the An inheritance Dynamics attempt to analyse the constitution chromosomes on the basis of sex-llmlted In, 365 morphogenesis and Inheritance in experimental reproduction, Studies on the of 187, 221 IV/TiGR-iTiON of retinal pigment in the eyes of Branchipus gelidus, 143 T H An attempt to analyse the constitution of the chromosomes on the basis of Morgan, sex-limited inheritance In Drosophlla, 365 VI INDEX Morphogenesis and inheritance in experimental reproduction, Studies on the dynamics of, 187 221 embryos without nerves The development and function of voluntary and cardiac, 159 .Muscle in Reproduction of Paramecium stant' culture medium aurelia in a 'con- of beef extract, 135 Reproduction, Studies on the dynamics of morphogenesis and Inheritance in, experimental 187 221 Reproductive activity of Infusoria, rhythms in the 339 p.\RAMEciDM, \ssortatlve mating, variability and inheritance of size in the conjugation of, Paramaecium aurelia in a constant' culture medium of beef extract The reproduction of 135 Retinal pigment In the eyes of Branchlpus gelidus, migration of, 143 Rhythms in the reproductive activity of Infusoria, ' Parker, G H and Parshlet, H M The reactions of earthworms to dry and to moist surParshley, H M Parker G H and The reactions of earthworms to dry and to moist surfaces, 361 Stewart ^Ex-LiMiTEn tempt faces 361 Paton 339 Experiments on developing chickens' eggs, 469 inheritance in Drosophlla, An atto analyse the constitution of the chro- mo-somes on the basis of, 365 '\701.rNTARTandcardiac muscle inembryos without nerves The development and function of, 159 Photogenic organs, with special reference to the LampjTidae, On the structure, physiology and use of, 415 Planarla and other forms new zooids in, 221 Planarla dorotocephala ance of anterior TVT^iLSON, H III The formation of ated Physiological domin- over posterior regions in the dominance the behavior of the dissociAleyonarla and hydroids, WooDBUFF, L.L and G A Baitsell Rhythms in the reproductive activity of Infusoria 339 Woodruff, L L and G A Baitsell The reproduction of Paraemeclum aurelia in a 'constant' culture pj EGULATiON of Planarla dorotocephala II regions in the, 1S7 On in Asterias, 281 II regulation of 187 ological v., cells medium of beef e.'rtract, 135 Physi- of anterior over posterior '061DS In Planarla and other forms, formation of new, 221 III The ASSORTATIVE MATING, VARIABILITY AND INHERITANCE OF SIZE, IN THE CONJUGATION OF PARAMECIUM' H From S JENNINGS the Zoological Laboratory, Johns Hopkins University SIXTEEN FIGURES CONTENTS ^ Problems outlined The I facts as to relative size, variability, and assortative mating in con- ^ jugation • Methods Fundamental measurements Relative size of conjugants and non-conjugants Relative variability of conjugants and non-conjugants ^ ^^ 16 17 Causes of the lessened variability of conjugants Gametic differentiation Equalization Growth 17 18 18 : Increase in size and variability of the conjugants before fission Racial differences Assortative mating • Pearl's explanation Observation of the process of conjugation Correlation in size in the members of pairs of conjugants Meaning of the coefficients of correlation Correlation in different classes of cultures Wild cultures, of unknown racial composition Cultures containing pairs belonging to two different species Conjugation within pure races Mixtures of two known races To what is due the incompleteness of correlation? Slight differences of less effect than great ones Different categories of pairs following different rules • ^2 23 23 24 28 28 37 37 39 *! " ^" *" 51 52 Unevenness at the anterior ends ' 20 Third of a series of papers on Heredity, Variation and Evolution in Protozoa THE JOURNAL OF EXPERIMENTAL ZOdLOnr, VOL JDLY, 1911 11, No Z H S JENNINGS Causes of the correlation Assortative mating a Correlation between the length anterior to the mouth and the total length gj b High variability c Low of the posterior region correlation of parts before 63 64 64 and behind mouth Correlation of pairs greater for parts anterior to mouth correlation of parts posterior to mouth f Region in front of the point where the two conjugants separate Equalization during mating Correlation of pairs after separation _ d e Low 64 65 65 67 Change 60 60 in variability and correlation of parts after separation Correlation of pairs not due to equalization Change of size during union Differential contraction due to killing fluid Local or temporal differentiations in the culture 70 73 74 77 80 Other suggested causes 82 Correlation in breadth 82 a Flattening at the time of conjugation 83 b Correlation in breadth in pairs after separation 84 c Correlation in breadth not due to equalization 85 Historical and comparative 85 Conclusions on assortative mating 89 II Consequences of the differentiation of the conjugants and of their assortative mating $9 Consequences of the decreased size and lessened variability 90 Are the extreme specimens excluded from the new generation? 90 Relative size of progeny of conjugants and non-conjugants; changes in size due to conjugation 92 a Comparison of progeny of conjugants and non-conjugants in pure • 93 races b Comparison of progeny of conjugants and non-conjugants wild culture in a 97 Historical 100 c Exceptional case 101 d Summary 103 Increase in variability as a result of conjugation Do Inheritance from unequal pairs pairs of different size give progeny of different size? Summary 104 104 106 106 Literature cited 109 Appendix: tables of measurements 110 CONJUGATION IN PARAMECIUM INDEX OF TABLES 11 12 13 14 15 16 17 H S JENNINGS have not been hitherto have been dealt with by previous far as possible, not only with matters that treated, but even with those that investigators, in the latter case confirmiHg or criticizing their This does not implj' a precedent suspicion as to the accuracy of the work thus gone over; it is done only in pursuance of a general policy, for one often finds matters of great import where they are least expected Furthermore, the recent discovery of the existence of many diverse races in Paramecium makes it needful to reexamine many phenomena in relation to the part played in them by these different races In anj' case, in results this difficult field independent confirmation of another's results is decidedly worth while It will be well to set forth here an outline of the questions with which a thorough investigation of the size relations in con- jugation would have to deal To Pearl ('07) we owe the discover}' of certain most interest- ing relations between the conjugating individuals of Paramecium By an elaborate statistical investigation he showed (1) that the conjugants of a culture of Paramecium are much less variable than the non-conjugating population, and have (as had before been noticed) a smaller mean size; (2) that there is a marked degree of correlation in size between the members of pairs in Paramecium; smaller individuals being found mated with smaller, larger with larger With these important mattei's, particularly in their relation to the existence of diverse races, we shall have to deal thoroughly The precise questions here are as follows: WTiat are the facts as to the relative variability and size of conjugants and non-conjugants, and what is their relation to the existence of races of diverse size? Wliat are the facts as to assortative mating; ing conditions, its peculiarities and its determin- limitations; its relation to the existence of diverse races? What are the results, in inheritance, variability lution, of the smaller size and decreased and evo- variability of the conju- compared with the non-conjugants? If we breed from a number of the conjugants, thej' give progeny that are (a) smaller, or (b) less variable, than the progeny of the larger, more gants, as 458 of the E The J LUND process of photogenesis cytoplasm and is independent of the \'itahty a resultant of the interactions of formed substances in the presence of water and oxygen It is highly is partakes of the nature of an oxidation but this has yet not been demonstrated for the photogenic process in the Lampyridae if in any animal ])r()l)al)le that it been shown that photogenesis is incident upon the compound the photogenic granules giving staining reactions like those of lecithin and different from those of the true fats, and that this nitrogenous compound apjiears at least in part at the end of the process in tlie form of a nitrogenous waste ])roduct This crystalline sul)stance appears fi-om its reactions to be allied to or itientical with some of the split jiroducts () It has — utilization of a nitrogenous of nucleic acid The product dorsal layer cells No become the repositories for the waste direct transformation of the jihotogenic cells, as such, into cells of the dorsal layer takes S The photogenic i)lace jirocess is localizetl in and ailjacent to the cytoplasm of the jihotogenic cells and especially (as far as could be determined) where the cytoplasm of the tracheal end cell, and tracheole is applied to the photogenic cell The increase in intensity of the light resulting from increase in pressure is due to th(> increased oxygen content in the i-egif)ns where photogenesis takes place Changes in the oxygen content is not the primary means of control of the organs 10 The primary control of the oi-gan is by nerves in dii-ect connection with the photogenic tissue and not b.y an external respirator^' muscular mechanism The termination of nerve fibers in the tracheal end cells as Bongardt states he found in Lani])yris splendidula is supported by the fact that pliotogenesis may l)e limited to points which can structvu'ally only l)e I'efei'red to the tracheal end cells and that upon increased stinmlation a phenomenon similar to a 'spread' of the stimulus takes place Furthermore the photogenic to mechanical stimuli 11 A tissue is irritable direct control i-elation exists and responds locally between the jihotogenic organs and the nerve centres of the head This is apjiarently PHOTOGENIC ORGANS 459 correlated to the relation which (wists between the degree of development of theeyes and the photogenic organs, i.e., the extent of development of the eyes is in direct proportion to the extent of development of the photogenic organs 12 The positive response to light b\' some photogenic organisms results in bringing the eggs and sperm in nearer proximity to each other in cases where these are set free in the water before This has been shown for Odontosyllis enopla bjThis is also very probably ti-ue foi- OdonGalloway and Welch In other cases the response may tosyllis pachydonta (?) Verrill been found for Photinus pyralis by lead to copulation as has Osten-Sacken, and for Photinus consanguineus and P scintillans by AIcDermott fertilization Zoological Laljoratory Johns Hopkins University, September 1911 20, LITEHATUHE CITED BoNGARDT, 1903 J Zeit.s The Kenntniss der Leiichtdi'gane cinheimi.sher zur Beitijige Lamjiyriden f wiss Zool., Bd 7.5, pp 1-1.') Columbia Cl.\kk, E D 1910 Dubois, R Contribution a I't-tude de la production de la lumiere par Les Elaterides luniinaux Bull 8oc Zool France Annee jjlant o.xidascs Dissertation Univer.sity 1886 litres, les II, pp 1-275 1892 Sur le mdchanisme de la production de la lumiere chez I'Orya barbarica de Algerie Comptes Rend Acad Sci France, 1892, cxvii, pp 184-G Physiological Liglit 189.5 Smitlis Inst., Wash., D C Report for 1895, i)p 413-431 EiMEK, T Bemerkungen 1872 Archiv Emery, C 1884 Bd iiber die mikr .Vnat., Bd f Untersuchungen Leuchtorgane der Lampyris splendidula p 6.53 iiber Luciohi italica Zcits f wiss Zooh, 40, pp 338-3.55 1885 La luce delhi Lticiohi italica, osservata col Microscopio Soc Entomol Ital Ann Soc, 1886 18S6 Ann La 17, Trim Bull Roy .Micr Bull .Soc l^ntomol Ital., 3/'4, p .351-5 .\lso lour p 2.34 luce negli aiuori dcllc Luciolc IS, p 406 400 E E.MEKV, C 1886 Sui- lo liimiero Xat (Geneve) et des Lucioles (Luciola italics) T (3), LUND J Arch Sc Phj-s 14, no 9, p 272-.J \V., and Welch P S Hill Studies on a jjhosphorcseent Berinudan annelid, (.)dontosyllis enopla \'errill Trans .\ni Mirr Soc, January 1911, vol 30, pp 13 G-\LLn\vAV, T Heine.m.vn 1872 tHDer die Leuclitorgane der Leuohtkafer .\rrliiv f niiUr .Vnat., Zur \natonue und Cucujos (Pyrophorus) Pliysi(ilo{»ie 18,8(1 HoLiiGHEX \rchiv in der Leuclitorgane Mexikanischcr mikr f Cruz vorkonnuen^/^?- EXPERIMENTS ON DEVELOPING CHICKENS'S EGGS STEWART PATON Biological Laboratory, Princeton Universily The results of observations made upon the de\'eloping eggs of several species of selachians suggested the possibility of repeating these experiments, with certain modifications, upon the embryos of other vertebrates The egg admirably adapted for studying and myotom without in the normal relationship of the growing organany way disturbing ism, but on account of the difficulty of seciu-ing these eggs in large quantities a search was made for material which could be more easily obtained Observations made upon several species of lizards, frogs and fresh water fish were for many reasons unsatisof the primitive scyUium canicula movements is of the heart factory and attention was then directed to the chicken's egg Experimenters have at various times removed the fertilized egg from the shell, and after detaching the embryo, have succeeded in keeping the latter alive for some time not, however, exceeding a period of twelve hours After many futile attempts, an operative technique has been devised making it possible in the majorit}^ of instances to remove the fertilized chicken's egg from the shell, place it in a glass dish containing fluid and return the receptacle to the incubator, when development under the conditions to be mentioned proceeds uninterruptedly The egg freed from the shell becomes an object for observation and experiment, and not only the incidence of the primitive movements of the heart, but also many other interesting phenomena connected with the growth of the embryo may be observed and recorded The technique employed in follows THE JOURNAL OF EXrERlMENTAL Zoot.OQT, VOL H, NO 469 the operations is as 470 STEWAKT PATON All solutions are sterilized in the autoclave Such a small during the process that in the majority not often necessary to replace it but, if in certain quantity of fluid of cases cases it is it is is lost essential, this may easily be accomplished if the fluids In order to shorten the operation as much as possible, and to minimize the risk of exjwsing the sterilized fluids to the air, the solutions are poured into dishes in which the eggs are to be placed, covered and put in the thermostat The lids, which should be mm to 10 mm have been sterilized in graduated larger than the dishes, rest string, and by means upon flasks collars of cotton held in place by Care should be taken that the cotton does not come into contact with the fluid in the dishes, and on the other hand, these collars must be sufficiently thick to raise the lids and give plenty of opportunity for the passage of air Many embryos are killed by a deficient supply of oxygen The cotton acts as a filter and prevents all bacteria except those within the shell from contaminating the this free access is given to the air fluids in the dishes After the egg has been for the requisite amount of time in the incubator, it is removed, the shell is wiped off with 95 per cent or preferably 100 per cent alcohol, and with the aid of a pair of forceps that have been sterilized, an opening with smooth edges and the contents allowed to slide gently into the dish containing the fluid which should be of the same temperature is made in it as the egg If the dish contains sufficient fluid the egg will quickly right that the embrj^o is on top Even slight differences of temperature seem to be fatal to the success of the experiment, and on this account, it is better to conduct the whole process of transferring the egg from its shell to the dish in some kind of warm chamber, such an one as can readily be constructed in the laboratory Wlien the egg is in the dish and covered, the process of development may be observed through the glass top without exposing the contents to the air The earlier in development that the transfer is made, the greater is the chance of failure, but when the embryo has attained the size seen under normal conditions at about the 26th-27th hour itself so EXPERIMENTS ON DEVELOPING CHICKENS'S EGGS of incubation, the operation is 471 nearly always accomplished with- out serious injury to the growing organism The action of a variety of fluids upon the embryo were observed of some of the effects that were noted will and a brief account now be given: The constituents of Ringer's solution were tried singly and in from 0.5 per cent to NaCl combination per cent if uncorabined, with other salts at once killed the embryo, but development although apparently taking place at a slower rate than normal, followed when the egg was placed in 0.7 per cent solution of NaCl to which 2.7 cc of a molecular CaClo solution was added The record of all my experiments show that the rate of development is retarded in the sodiumcalcium solutions, and the vitality of the embryo is also weakened The extremely interesting fact in connection with this experiment is that the presence of such minute quantities of calcium is sufficient not only to protect the Ufe of the embryo, but also in varying strength to insure at the proper time the incidence of the cardiac move- The same observation with practically similar results was made upon the eggs of trout In the presence of these minute quantities of calcium, when combined with sodium, the regular ments and rhythmical pulsations of the heart begin, for several hours with increasing force embryo dies The calcium alone and and are continued rate, but later the not sufficient to insure the continuation In solutions to which KCl (6.3 cc of a molecular solution) has been added, in addition to NaCl and CaCj growth seems to take place at a normal rate of is the developmental proce.sses The effect of and its MgCls alone upon the growth of the embryo chick movements of the heart has not relations to the primitive been experimentally deteiinined, but solutions containing my impression is that the MgClo when not combined with CaCl2 and NaCl are highly toxic The effect of urea in either alone or to strengths varying from 0.5 to per cent combined with NaCl does not act as a stimulus growth and the embryo soon Containing this substance dies when placed in solutions STEWART PATON 472 Embryos detached from the egg and floated in any of the solu- tions named, Hve but a short time and the incidence of the primitive movements of the heart in these detached specimens is never observed Caution should be observed in basing any deductions in regard to the immediate action of the various salts upon the incidence It does not seem probable that the detached embryos to develop is purely the result of shock, but is due chiefly to the absence of nourishment supplied of the cardiac pulsations failure of the by the egg ... anterior ends ' 20 Third of a series of papers on Heredity, Variation and Evolution in Protozoa THE JOURNAL OF EXPERIMENTAL ZOdLOnr, VOL JDLY, 1911 11, No Z H S JENNINGS Causes of the correlation Assortative... size of progeny of conjugants and non-conjugants; changes in size due to conjugation 92 a Comparison of progeny of conjugants and non-conjugants in pure • 93 races b Comparison of progeny of conjugants... assortative mating, of the conditions experimental this on which it depends, of races, and particularly of its relation to its the existence of diverse consequences in the later history of the stock