DR. MARTIN BARRY'S RESEARCHES IN EMBRYOLOGY. 333 



119. Explanation of the Plates. 



N.B. In all thejigures the same letters denote the same objects, the alphabetical order 

 of these letters corresponding with the order of position of the parts in proceeding out- 

 wards from the centre of the ovum : viz. 



a. Fluid, or graniilous fluid, of the germinal vesicle. 



b. Germinal spot or germinal spots. 



c. Germinal vesicle. 



d. Yelk. 



d'. Spot on the internal surface of the membrana vitelli in the Frog. 



e. Membrana vitelli. 



f. Chorion, — also ovum. 



g. Peculiar granules, first constituting the envelope of the germinal vesicle, 



next contained in the fluid of the ovisac, and lastly arranging themselves 

 to form : 



g'^. Tunica granulosa. 



g'^. Retinacula. 



g^. Membrana granulosa. 

 h. Ovisac, or proper membrane of the ovisac. 

 i. Proper covering or tunic of the ovisac, — also blood-vessels. 



h i. Graafian vesicle, or corresponding structure (capsule) (consisting 

 of^ + i). 

 k. Stroma, Parenchyma, substance in which the ovisac is imbedded, or couch. 

 /. Peritoneum. 



i k I. Pedicle (formed by the union of z, k and /). 

 XX. "Stigmate" of Baer. 

 * Oil-like globules. 



g*. Isolated spots (consisting chiefly of ^ + *). 



PLATE V. 



Fig. 1. Rabbit (JLepus Cuni cuius, Linn.). Very early stages in the formation of 

 the ovum (14.). c. The germinal vesicle containing (a) fluid, and in one 

 instance {b) a well-marked spot. These germinal vesicles measured from 

 -rhr'" to -sV'" (Paris line) in their long diameter, g. An envelope of pecu- 

 liar granules (14.). The ovisac is not yet formed. Compare with fig. 2. 

 from the Cat, and figs. 19. and 20. from the Pigeon. 440 diameters. 



Fig. 2. Cat {Felis Catus, Linn.). Stages in the formation of the ovum (16.) nearly 

 corresponding to some of those seen in fig. 1., but the germinal vesicle 

 in this instance is concealed (12. 24.). g. Envelope of peculiar granules; 



