68 4 



MAMMALIA. 



ature of the blood is about 25°-28° C, and is noteworthy in 

 being unusually variable. 



The ureters open, not into the bladder, but into the 

 urogenital canal, as they do in the embryos of higher 

 Mammals. 



The testes remain in the abdomen. The left ovary is 

 larger than the right, as in Birds. The vasa deferentia 

 open separately into the urogenital canal. So in the 



-vj. 



•is'B' ' 



Fig. 299. — Urogenital organs 

 of male duckmole, — After 

 Owen. 



Bl., Bladder; w., ureter; v.d., vas 

 deferens; r., rectum;,^/., gland ; cl., 

 cloaca ; /., penis ; u.g.c, urogenital 

 canal. 



Fig. 300. — Urogenital organs 

 of female duckmole. — After 

 Owen. 



Ov., Ovary ; od., oviduct ; od'., internal 

 opening of oviduct; «/., "uterine" 

 region ; ut '., opening of " uterine" 

 region into sinus; «. } ureter; r., 

 rectum; uv., bladder; ug., uro- 

 genital sinus ; cl., cloaca. 



female do the oviducts, and these have no fringed fim- 

 briated apertures nor distinct uterine region. The penis is 

 attached to the ventral wall of the cloaca, and the uro- 

 genital canal communicates both with the cloaca and with 

 the canal of the penis. The whole structure resembles in 

 many ways the copulatory organ of certain Reptiles and 

 Birds. 



The ova are large, with abundant yolk, and undergo 

 meroblastic segmentation. The Prototheria are oviparous. 



