6G BIBLIOGRAPHY. 



The yolk-sack persists long after hatching, and is gradually 

 absorbed. There is daring the stages either just before hatching or 

 shortly subsequent to hatching (Cyprinus) a rich vascular develop- 

 ment in the mesoblast of the yolk-sack. The blood is at first con- 

 tained in lacunar spaces, but subsequently it becomes confined to 

 definite channels. As to its exact relations to the vascular system 

 of the embryo more observations seem to be required. 



The following account is given by E-athke (No. 72*) and Lereboullet 

 (No. 71). At first a subintestinal vein (vide chapter on Circulation) falls 

 into the lacunse of the yolk-sack, and the blood from these is brought back 

 direct to the heart. At a later period, when the liver is developed, the 

 subintt'stinal vessel breaks up into capillaries in tlie liver, thence passes 

 into the yolk-sack, and from this to the heart. An artery arising from 

 the aorta penetrates the liver, and there breaks up into capillaries con- 

 tinuous with those of the yolk-sack. This vessel is perhaps the equiva- 

 lent of the artery which supplies the yolk-sack in Elasmobranchii, but it 

 seems possible that there is some error in the above description. 



BlBLIOGKAPHY. 



(55) Al. Agassiz. "On the young Stages of some Osseous Fishes. I. De- 

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(=,6) Al. Agassiz. "II. Development of the Flounders." Proceedings of the 

 American Acad. of Arts and Sciences, Vol. xiv. Presented June, 1878. 



(57) K. E. v. Baer. Untersuclutngen iiber die Entwicklungsgeschichte der Fische. 

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(s8) Ch. van Bambeke. "Premiers effets de la fecondation sur les ceufs de 

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(59) Ch. van Bambeke. "Kecherches sur I'Embryologie des Poissons Osseux. " 

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(60) E. v. Benedeu. "A contribution to the history of tLe Embryonic develop- 

 ment of the Teleosteans. " Quart. J. of 3Iicr. Sci., Vol. xvm. 1878. 



(61) E. Calberla. "Zur Entwicklung des Medullariohres u. d. Chorda dorsalis 

 d. Teleostier u. d. Petromyzonten." Morpholoyisches Jahrbuch, Vol. in. 1877. 



(62) A. Gotte. "Beitrage zur Entwicklungsgeschichte der Wirbelthiere. " Archiv 

 f. mikr. Anat., Vol. ix. 1873. 



(63) A. Gotte. '.'Ueber d. Entwicklung d. Central-Nervensystems der Teleostier." 

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(64)' A. Gotte. " Eutwick. d. Teleostierkeime." Zoologischer Anzeiger, No. 3. 

 1878. 



(6s) W. His. " Untersuchungeu u'ber die Entwicklung von Knocheufischeu, etc." 

 Zeit. f. Anat. n. Entwicklungsgeschichte, Vol. i. 1876. 



(66) W. His. " Untersuchungen iiber die Bildung des Knocheufischembryo 

 (Salmen)." Archiv f. Aunt. u. Phi/siol., 1878. 



(67) E. Klein. ' "Observations on the early Development of the Common Trout." 

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(fix) C. Kupffer. "Beobachtungen iiber die Entwicklung der Kuocheufische." 

 Archir f. mikr. Anat., Bd. iv. 1868. 



(69)' C. Kupffer. Ueber Laichen u. Eiitic/rklinifi des Ostsee-Herinns. Berlin, 1878. 



(70) M. Lereboullet. "Becherches sur Ic developpement du brochet de la perche 

 et de 1'ecrevisse." AximJes des Sciences Nat., Vol. i. , Series iv. 1854. 



(71) M. Lereboullet. "Becherches d'Embiyologie comparee sur le developpe- 

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