IO8 DEVELOPMENT OF THE ELASMOBRANCH FISHES. 



LIST OF WORKS REFERRED TO. 



Gegenbaur. Anat. der Wirbelthiere, III Heft, Leipzig, 1873. 



A. Gotte. Archiv. fur Micr. Anat., Vol. x. 1873. "Der Keim der Forelleneies," 



Archiv.filr. Micr. Anat., Vol. IX. 1873. " Untersuchung liber die Entwickelung 



der Bombinator igneus," Archiv. filr Micr. Anat., Vol. V. 1869. " Kurze Mit- 



theilungen aus der Entwickelungsgeschichte der Unke," Archiv. fur Micr. Anat., 



Vol. IX. 1873. 

 Kupffer. Archiv. fur Micr. Anat., Vol. n. 1866, p. 473. Ibid. Vol. IV. 1868, 



p. 209. 

 Kowalevsky. " Entwickelungsgeschichte der Holothurien," Memoirs de fAcad. 



Imper. des Sciences de St Petersboiirg, vii ser. Vol. xi. 1867. 

 Kowalevsky, Owsjannikow, uncl Wagner. "Entwickelung der Store," Bulletin der 



K. Acad. St Petersbourg, Vol. XIV. 1873. 

 Kowalevsky. " Embryologische Studien an Wurmern und Arthropoden," Memoirs 



de rAcad. Imper. des Sciences de St Petersbourg, Vol. xvi. 1871. 

 E. Ray Lankester. Annals and Mag. of Nat. History, Vol. xi. 1873, P- 81. 

 W. Mliller. " Ueber die Persistenz der Urniere bei Myxine Glutinosa," Jenaische 



Zeitschrift, Vol. vii. 1873. 



Oellacher. Zeitschrift fur IViss. Zoologie, Vol. XXIII. 1873. 

 Owsjannikow. "Entwickelung der Coregonus," Eul. der K. Akad. St Petersbourg, 



Vol. xix. 



Romiti. Archiv. filr Micr. Anat., Vol. IX. 1873, 

 Waldeyer. EierstocR u. Eie. 



EXPLANATION OF PLATES 3 AND 4. 



COMPLETE LIST OF REFERENCE LETTERS. 



a I. Alimentary canal, a o. Dorsal aorta, an v. Auditory vesicle, b d. Forma- 

 tive cell probably derived from the yolk, ca v. Cardinal vein, c h. Notochord. 

 c H . Thickening of hypoblast to form the notochord. e b. Line indicating the edge 

 of the blastoderm, e p. Epiblast. e p' . Epidermis, e r. Embryonic rim. e s. Em- 

 bryonic swelling, g I. Glosso-pharyngeal nerve, h. Head. ///. Heart, h y. Hypo- 

 blast. //. Lower layer cells. I y. Line of separation between the blastoderm and 

 the yolk. m. Mesoblast. m c. Medullary canal, m g. Medullary groove, m p. 

 Muscle-plate, m p'. Early formed mass of muscles, n. Peculiar nuclei formed in 

 the yolk. '. Similar nuclei in the cells of the blastoderm, n a. Cells which help 

 to close in the alimentary canal, and which are derived from the yolk, n y. Network 

 of lines present in the food-yolk, o I. Olfactory pit. op. Eye. ov. Oviduct, p n. 

 Pineal gland, p ov. Projection which becomes the ovary. //. Pleuro-peritoneal 

 cavity. //' Remains of pleuro-peritoneal cavity in the head, pr v. Protovertebrse. 

 p wd. Primary points of involution from the pleuro-peritoneal cavity by the coalesc- 

 ence of which the Wolffian duct is formed, s g. Segmentation cavity, j o. Somato- 

 pleure. so s. Stalk connecting embryo with yolk-sac, s p. Splanchnopleure. sp n. 



