246 



ANATOMY OF VERTEBRATES. 



within the common sperm-cell, fig. 



124 



Earliest stages of tlie formation of the ovarian egg in 

 the Bird, cccviii. 



macula, the ordinary 

 LCters of the ^ germinal 

 vesicle.' This is shown, in focus, at C ; the epithelium of the ovisac 



122 : here they are agglutinated 

 together, either in irregular 

 groups; or, as in the Cantores, 

 in a regular bundle, with the 

 spiral bodies at one end and 

 the tails extending, parallel, 

 to the other,fig. 123. In both 

 cases the spermatozoa are set 

 free by rupture and solution 

 of the sperm-cell: in the Can- 

 tores they are then found fas- 

 ciculate in the ' tubuli testis,' 

 whilst in other birds they are 

 irregularly dispersed. 



§ 168. Female Organs and 

 Ovulation of Birds. — The 

 ovarium of the Bird consists 

 essentially of the germ-cells, 

 with the stroma or blastema 

 modified by their presence, 

 and the vitelline matter su- 

 peradded to the germ-cell. 

 The formative processes are 

 most clearly traceable in the 

 smaller sinoino:-birds. In fio;. 

 124, A, the small clusters of 

 granules indicate the begin- 

 ning of the ova in the 

 ovarian stroma : in larger 

 clusters a clear point ap- 

 pears, which in the largest 

 assumes the character of a 

 germ-cell surrounded with 

 opaque minute granules. The 

 almost contemporaneous for- 

 mation of the ^ ovisac' 

 (Barry) soon manifests itself 

 by its lining of epithelial 

 cells, ib. B, at which period 

 the germ-cell manifests, by 

 its 

 characters of the ^ germinal 



