RUDIMENTARY ORGANS OF ANIMALS 13 "7 



57, c and D). This development was attended by 

 important modifications, further instances of de- 

 generation taking place, and fresh organic connec- 

 tions being established. An examination of the 

 male and female sexes is necessary in order to 

 explain what really took place. 



In the male (fig. 57, c) the mesonephros began 

 to atrophy ; that part which was connected with 

 the testes was transformed into the epididymis and 

 the vas defer ens (e. and v.) of the true male genital 

 organs; the remaining part atrophied, and when the 

 permanent organization was attained, only persisted 

 in the form of a paradidyinis (p.) and a hydatid 

 (h.), organs which are quite without function in the 

 adult state. 



The discharging canal which, during the mesone- 

 phric stage was common to both urinary and genital 

 glands, remained simply in connection with the 

 testes, and then became the vas deferens (s.) of 

 which the cloaca having disappeared, the terminal 

 extremity became gradually individualized. The 

 permanent kidney (R.) became connected with a 

 freshx canal the ureter (u.) which was formed by 

 degrees at the expense of the primitive discharging 

 canal, and subsequently became separated from the 

 latter in order to empty itself into the bladder (v.). 



These changes were attended by a remarkable 

 evolution of Muller's -canal, which first increased 

 in size, and then at a certain point proceeded to 

 atrophy until all that remained were the distal and 



