DR. MARTIN BARRY'S RESEARCHES IN EMBRYOLOGY. 335 



separate existence of the former is seen in two places (49.)) ; h. germinal 

 spot ; c. germinal vesicle ; *. oil-like globules in the yelk, which consisted 

 besides of a pellucid fluid and minute granules ; g. peculiar granules ; 

 h. ovisac. No appearance yet of either the tunica granulosa (64.), the 

 retinacula (80.), the membrana granulosa (72.), or the proper covering 

 of the ovisac {77-)- 440 diam. 



Fig. 18. Pigeon {Columha livia, Linn.). A very early stage in the formation of the 

 ovum (15.). c. Germinal vesicle; a. its contents; *. oil-like globuies-j-. 

 Compare with fig. 30. Plate VI. from the Salmon. 440 diam. 



Fig. 19. Ditto. This figure corresponds to fig. 1. from the Rabbit, and fig. 2, from 

 the Cat (15.). g. Envelope of peculiar granules ; c. germinal vesicle ; 

 *. oil-like globules-}". 440 diam. 



Fig. 20. Ditto. Proper membrane of the ovisac {h.) in the course of formation 

 around {g.) the envelope of peculiar granules (23.). This appears to be 

 the stage succeeding that represented by the larger objects in fig. 1. from 

 the Rabbit, and by those»in fig. 3. from the Cat-}-. 440 diam. 



Fig. 21. Ditto. A multitude of ovisacs. Compare with fig. 10. from the Cat, and 

 fig. 32. Plate VI. from the Whiting. 150 diam. 



Fig. 22. Ditto. Incipient yelk (24.), consisting of oil-like globules (*) and a pellucid 

 fluid, c. Germinal vesicle; h. ovisac. Compare with fig. 15. from the 

 Hog. 440 diam. 



Fig. 23. Common Fowl {Phasianus Gallus, Linn.). Incipient yelk (24.), consisting 

 of oil-like globules (*) and a pellucid fluid, c. Germinal vesicle ; g. pe- 

 culiar granules; h. ovisac, v-o"'- Compare with fig. 15. from the Hog. 

 440 (?) diam. 



Fig. 24. Ditto. The yelk {d) just formed (consisting of oil-like globules and a fluid), 

 but the membrana vitelli not visible, h. Ovisac, -y'". The fluid of the 

 ovisac is obscurely granulous. 440 diam. 



Fig. 25. Ditto. Membrana vitelli (e) now visible. The yelk (d) consists still for 

 the most part of oil-like globules and a pellucid fluid, h. Ovisac. Com- 

 pare with fig. 16. from the Hog ; fig. 34. Plate VI. from the Turbot ; and 

 fig. 35. Plate VI. from the Salmon. 440 diam. 



Fig. 26. Ditto. An ovisac acquiring a proper covering or tunic, the union consti- 

 tuting the structure h i {^7-), still very transparent. The yelk is seen 

 escaping through the pedicle, which in this instance it has ruptured (32 

 Note), e. Membrana vitelli; g. peculiar granules. 100 diam. See the 

 ideal section Plate VI. fig. 38^. 



Fig. 26^. Cat {Felis Catus, Linn.). Oil-like globules (*) accumulated on the pe- 

 culiar granules {g) of the ovisac. (Plate VIII. fig. QQ. presents the same 

 objects in less number, and therefore appearing as isolated spots, g*). 

 t The objects represented in figs. 18. 19. and 20. were found lying among ovisacs apparently just formed. 



