56 



MORPHOLOGICAL TYPES 



In the female the mesonephros is entirely excretory in 

 function. The Wolffian ducts are swollen posteriorly to form 

 urinary sinuses which open to the cloaca by a urinary papilla. 



Fig. 29. — Scyllium : ventral view of a dissection of the urinogenital 

 system of a male adult. 



cd, collecting duct ; cl, clasper ; ek, excretory portion of the mesone- 

 phros ; ^alimentary canal cut ; p, pericardium ; pp, pericardio-peritoneal 

 canal indicated by an arrow ; ri, rudimentary opening of the Miillerian 

 ducts ; ss, sperm-sac ; t, testis ; ng, urinogenital papilla ; ve, vasa efferentia ; 

 vs, vesicula seminalis ; Wd, Wolffian duct or vas deferens. 



The right ovary hangs in the ccelom covered by a fold of 

 coelomic epithelium ; the left ovary disappears. The large 

 eggs when they are ripe drop free into the ccelom. They enter 



