664 



Comparative Morphology of Chordates 



extreme posterior ends of the Mullerian ducts, it would more logically 

 be called "vagina masculina." The bulbourethral or "Cowper's 

 glands" arise from the urethra at the region of the bulbus urethrae. 

 In the female are vestibular glands (or glands of Bartholin) open- 

 ing laterally into the vestibule. In position and relation totheurino- 

 genital passages, they correspond to the male bulbourethral. 



All three sets of glands — vesicular, prostate, bulbourethral — 

 are present in the majority of mammals, but there is much diversity 

 as to their relative degrees of development. When the glands of one 

 set are weakly developed or absent, the others are correspondingly 

 accentuated. The monotremes are described as having neither vesicu- 

 lar nor prostate glands, but very large bulbourethrals. Marsupials 

 have no vesicular and no obvious prostate glands, but the "prostatic 

 tract" of the urethra has a thickened and highly glandular wall and 

 there are commonly three pairs of bulbourethral glands. Vesicular 

 glands are especially strongly developed in such small and prolific 

 animals as insectivores and rodents (Fig. 500), but are lacking in 





Fig. 501. Section of the human prostate showin 

 hematoxylin and eosin. (Courtesy, Bremer- Vveatherford 

 tology," Philadelphia, The Blakiston Company.) 



lcretions. Zenker 

 Text-Book 



