I6S ZOOTOMY. 



170. The oviducts (od), delicate, plaited tubes, lying 

 dorsal and external to the corresponding ovaries, and 

 extending backwards into the pelvic cavity : for their further 

 characters see 194. 



171. The mesoarium (ms.o), a fold of peritoneum sus- 

 pending each ovary to the dorsal body-wall. 



172. The broad ligament (b.lg\ a fold similarly 

 suspending the oviduct : its anterior line of attachment 

 corresponds with the junction between the colourless and 

 pigmented regions of the peritoneum ( 133). 



In both sexes : 



173. The postcaval vein can now be seen to be formed 

 by the union of two veins lying within and parallel to 

 the epididymes or oviducts, and of which the right is 

 considerably larger than the left (Fig. 40). 



174. The whole extent of the lungs can now be seen : 

 they extend backwards to about the level of the gall-bladder, 

 the right fitting into a notch on the dorsal face of the right 

 lobe of the liver. 



175. The pleura, a fold of peritoneum connecting each 

 lung with the dorsal body-wall. 



XIX. Dissect off the muscles covering the ventral 

 surface of the pelvis, and cut away the median 

 portion of the pubes and ischia : also dissect away 

 the muscles attached to the inner surfaces of these 

 bones, portions of which will still be left obscuring 

 the contents of the pelvic cavity. Note 



176. The cloaca (Fig. 41, ^/ 1 ,V/ 2 ) or posterior division 

 of the alimentary canal, passing insensibly into the rectum 

 in front, and opening behind by the vent. 



177. The urinary bladder (/), a thin-walled sac 

 attached by its posterior extremity or neck to the ventral 



