820 



COMPARATIVE ANATOMY 



the canal Cowper's glands are found. These occur in almost all mammals 

 as scattered bodies or aggregated into larger masses surrounded by 

 smooth muscle. 



Considerable uncertainty exists as to the exact functions of these 

 glands. The removal of the prostate and the seminal vesicle in rats pre- 

 vents fertilization, while the secretion of the seminal vesicles increases 

 the activity of the spermatozoa. It seems probable that they are of great 

 importance in connection with fertilization. It has also recently 

 been shown that in some instances the* coagulation of the secretion of 

 these, glands closes the vagina after copulation and, thus prevents the 

 exit of the sperm. 



/,.. -// 



p. 9 



Fig. 462. 



A, B, The reproductive organs of the rabbit. A, male ; B, female. In each 

 case the dissection is made from the left side, the animal lying on its back, bl., 

 Bladder ; c.cav., corpus cavernosum ; c.cav.cl., corpus cavernosum of the clitoris ; 

 Cp., Cowper's gland; epd., cauda epididymis ; epd' ., caput epididymis ; F.t., 

 Fallopian tube ; f.o., fimbriated opening of the same ; ov., ovary ; p.g., perineal 

 gland ; pn., penis ; pr., prostate ; r.g., rectal gland ; rm., rectum ; sc.s., scrotal sac ; 

 sp.c., spermatic cord (cut short) ; sym., symphysis pubis ; t., testis ; ur, ureter; 

 ut., uterus ; ut.m., uterus masculinus ; uth., urethra ; v.d., vas deferens ; vag,, 

 vagina ; vest., vestibule. 



C, male, and D, female reproductive organs of dogfish, cl., Cloaca ; f.L, "falci- 

 form" ligament ; i.o.d., rudiment of the internal opening of the oviducts ; l.t., left 

 testis ; msn., mesonephros ; mso., mesorchium ; mtn., metanephros ; od., oviduct ; 

 oes., oesophagus ; ov., ovary ; r.t., right testis ; rm., rectum ; sh, shell gland ; sp.s., 

 sperm sac ; u.g.p. and v.p., urinogenital papilla ; u.g.s. and ur.s., urinogenital 

 sinus; ur., ureter; ur'., ducts of metanephros; v.eff., vasa efferentia ; ves.sem., 

 vesicula seminalis ; W.d., Wolffian duct or vas deferens. 



In the monotremes the cloaca serves as a general gathering place 

 for both the products of the urogenital sinus and the excreted matter 

 from the digestive canal and kidneys. This cloaca has only a single 

 opening to the exterior and it is from this fact that the name monotreme 

 has been taken. In all other mammals there is a definite and complete 



