340 DR. MARTIN BARRY'S RESEARCHES IN EMBRYOLOGY. 



PLATE VIII. 



Fig. 64. Hog (Sus Scrofa, Linn.). The ovum in its tunica granulosa (g^) at the 

 periphery of {h i) the Graafian vesicle, retained in this situation by {g^) 

 the retinacula (86,). 100 diam. 



Fig. 65. Mouse {Mus Musculus, Linn.). The same objects; but the ovum (f) in 

 this instance has not reached the periphery of {h l) the Graafian vesicle. . 

 c. The germinal vesicle, relatively very large ; h. the germinal spot. 



Fig. 66. Dog (Canis familiaris, Linn.). Four ova in one Graafian vesicle (88. Note), 

 and at or near to its periphery, g^. Retinacula ; the central portion of 

 the retinacula (g"^) reduced to little more than a membrane, which closely 

 surrounds (g^) the tunica granulosa, and appears to be the cause of the 

 well-defined contour of the latter, as seen in situ in this animal (88. Note). 

 g*. Isolated spots (59.), consisting chiefly of extremely minute oil-like 

 globules accumulated on the peculiar granules of the Graafian vesicle. In 

 this instance these spots were seen to be most numerous around some of 

 the ova. (Plate V. fig. 26^. presents these spots in close aggregation.) 



Fig. 67. Rabbit (Lepus Cuniculus, Linn.). An appearance frequent in this animal, 

 probably denoting a stage in the absorption of the ovum (60.). /. Dis- 

 tended chorion ; d. altered yelk ; c. the enlarged germinal vesicle ; b. the 

 enlarged germinal spot ; h i. Graafian vesicle. (The tunica granulosa 

 and retinacula have disappeared.) 100 diam. 



Fig. 68. Dog {Canis familiaris, Linn.). A patch of ovisacs {h) ^V to J-'" in length, 

 some of them passing into the state of Graafian vesicles, and among these 

 two (Ji i) that have become opake from the coverings acquired. One of 

 the ovisacs contains two ova (88. Note), g. Granules of the ovisac (in- 

 cipient retinacula?). 



Fig. 69. Sheep (Ovis Aries, Linn.). The cavity in which the ovisac is often found 

 (6.). The ovisac Qi) having been ruptured, the ovum {f) has escaped, 

 and is seen to have become flattened by pressure. The ovum bursting 

 before its exit, left behind its germinal vesicle (c). b. Germinal spot ; 

 g. peculiar granules of the ovisac ; h. substance in which the ovisac is 

 imbedded. 60 diam. 



Fig. 70. Cat (Felis Catus, Linn.). The chorion {f) not yet of such consistence .is 

 to resist even very gentle pressure, which, applied on one side, has forced 

 the now semifluid substance of the chorion to the other side (53.). e. Mem- 

 braiia vitelli (49. 53.) ; d, the yelk in an incipient state. 440 diam. 



Fig. 71. l:log {Sus Scrofa, Linn.). Portion of the membrana granulosa {g') re- 

 moved from the Graafian vesicle (73.). 100 diam. 



Fig. 72. Man (from Bernhardt). An ovum after maceration (50. 56.). d. The 

 yelk ; /. the chorion. The internal surface of the latter is the " mem- 



