Animal Morphology. 85 



urethra, bladder, kidneys, the vagina, and the uterus need no 

 discussion on the side of the female sex ; neither in the male 

 of the oneness of the mucous membrane of the urethra, 

 bladder, ureters, and kidneys, nor yet of the vas deferens, and 

 the tubuli uriniferi of the same sex, as those are matters of 

 simple dissection and careful tracing. They are essentially 

 continuous mucous membranes, even to the Fallopian tubes 

 and fimbrias of the female. The muscular membrane 

 is found in the bladder and urethra, chiefly in the male 

 sex, and in the uterus and vagina additionally in the 

 female sex ; but in neither is there any proper serous 

 membrane. 



For both the serous membranes of the ovaries in the female 

 sex, and the tunica vaginalis propria and reflexa in the male, 

 are properly considered as pertaining to the peritoneum of 

 the abdominal viscera, and in nowise belonging to the genito- 

 urinary system. But, however displaced and differentiated, 

 it may be asked, Where do you find the serous membrane ? 

 Some would say, in the differentiated and homologous struc- 

 tures of the labia minora and clitoris of the female sex, 

 and the corpora cavernosa and corpus spongiosum of the 

 male sex ; inasmuch as in one respect these may have a 

 remote relation to serous membrane in function, since they 

 are essentially mechanical in their function, and aid in ac- 

 complishing an end which is altogether impossible to be 

 accomplished as an active vital function, unaided by a func- 

 tion which in itself is so entirely mechanical, and of inde- 

 pendent and perfect adaptation ; but these probably belong 

 to the Mammary system. 



Yet it must be borne in mind that neither male nor 

 female sex are complete in themselves, and, by a peculiar 

 differentiation, the ends of vital operation cease by their 

 own independency of action ; and not until the separate 

 mechanisms are united by intercourse in the continuance 



