3,38 DR. MARTIN BARRY'S RESEARCHES IN EMBRYOLOGY. 



one part of the surface of the yelk is seen a pellucid space, which is the 

 situation of the germinal vesicle. This figure presents the state of the 

 ovum vi^hen absorption is commencing (60. Note.). 440 diam. 



Fig. 45. Hog {Sus Scrofa, Linn.). The tunica granulosa {g^) removed entire from 

 the ovisac, with some adherent granules, which form part of the rup- 

 tured retinacula (g"^). h. Germinal spot; c. germinal vesicle; d, yelk; 

 f. chorion. 150 diam. 



Fig. 46. Ditto. The tunica granulosa {g^) relatively thicker than the last, from a 

 loosening of its granules by incipient liquefaction (g"^). Adherent gra- 

 nules of the ruptured retinacula. A pellucid space is seen at one part of 

 the surface of (d) the yelk, which is the situation of the germinal vesicle. 

 This figure presents an early stage in the absorption of the ovum (60. Note.). 



Fig. 47. Dog (Canis /ami liar is fIjifiN.). The tunica granulosa (g^) removed entire 

 from the ovisac, with part of the ruptured retinacula (g'^) adherent. 

 d. yelk ; /. chorion. 150 diam. 



PLATE VIL 



Fig. 48. Dog {Canis familiaris, Linn.). Incipient separation of the granules from 

 the fluid of the ovisac (78.). g"^. First appearance of the retinacula; 

 d. yelk, the only portion of the ovum in this instance visible from the 

 exterior of {h i) the Graafian vesicle. 60 diam. 



Fig. 49. Guinea Pig (Cohaya Aperea, Cuv.). The same objects in a stage more 

 advanced (78.). g^. Tunica granulosa. 150 diam. 



Fig. 50. Rabbit {Lepus Cuniculus, Linn.). A stage still more advanced (79)- The 

 peculiar granules of the Graafian vesicle (h i) are now seen to have be- 

 come arranged into three incipient structures, viz. ^^ the tunica granu- 

 losa (64.) ; g"^. the retinacula (80.) ; g^. the membrana granulosa (72.) ; 

 f. the chorion. 100 (?) diam. 



Fig. 51. Sheep {Ovis Aries, Linn.). The retinacula {g'^) supporting the ovum {f) 

 in the centre of {hi) the Graafian vesicle (80.). The tunica granulosa, 

 though probably formed, is not distinctly visible. 60 diam. 



Fig. 52. Ox (^Bos Taurus, Linn.). The same objects, together with {g^) the tunica 

 granulosa. 100 diam. 



Fig. 53. Ditto. The retinacula (^-) removed from the Graafian vesicle, g^. Tu- 

 nica granulosa; f. chorion (ovum). 100 diam. 



Fig. 54. Dog {Canis familiar is, Linn.). The same objects, though in this figure 

 the membrane of the central portion of the retinacula {g^) is closely ap- 

 plied to, and hence scarcely distinguishable from, the tunica granulosa 

 {g^) (88. Note), c. Germinal vesicle in the centre of the yelk. 100 diam. 



Fig. 55. Ox {Bos Taurus, Linn.). The ovum (/) approaching the periphery of 



