— 38 — 



organs differ greatly in appearance ; the testes in this species 

 are long and narrow, while the ovaries are short and broad. 

 These organs are situated one on each side, between the 

 layer of adipose tissue which surrounds the alimentary canal 

 and the layer of the same tissue which is attached to the 

 sides of the wall of the abdomen. The testes extend from 

 near the middle of the third abdominal segment to near the 

 posterior border of the sixth abdominal segment. The 

 ovaries extend from near the middle of the fourth abdominal 

 segment to near the middle of the fifth abdominal segment. 



Determine the sex of the specimen that 3^011 are studying 

 and do the work indicated below for that sex. 



Reproductive Organs of the Male. — Note the shape of a 

 testis, .the connection of it with the respiratory system, the 

 groove in the middle of its mesal aspect, and the vessel in 

 the bottom of this groove. This vessel is the vas deferens 

 (plural, vasa deferentia) and is the outlet of the testis ; it 

 extends caudad to near the caudal end of the body. The 

 cephalic end of the testis is supported by the ligament of the 

 viscera already described. 



Make drawings showing the external form of a testis. 



Trace out the course of the vas deferens. This will require 

 very careful dissection, especially in the ninth abdominal seg- 

 ment, where the vas deferens passes under a muscle. 



The triangular organ into which the two vasa deferentia 

 empty is the vesiculee scminalcs. If the specimen has been 

 opened on the ventral side, the visculae seminales will lie on 

 the alimentary canal, but if it has been opened on the dorsal 

 side it will be necessary to cut the intestine and turn back 

 the caudal part of it in order to see the visculae seminales. 



The tube extending from the vesiculae seminales to the 

 external opening of the reproductive organs is the cjacn- 

 latory duct. 



Make a drawing showing the relations of the testes, vasa 

 deferentia, vesiculae seminales, and ejaculatory duct. 



