No. 3.] CLIXOSTOMUM HETEROSTOMUM. 701 



caudal pore. The subcuticular canals joining one another for 

 the most part at right angles, the transverse canals being much 

 wider than the longitudinal, form a most conspicuous network, 

 which may be injected with carmine by certain methods (R. R. 

 Wright (6) ). A connection exists between this network and 

 the lateral longitudinal canals which run at the sides external 

 to the intestinal coeca. These lateral canals arise from two 

 branches on each side anteriorly, the smaller joining the larger 

 at about halfway, and posteriorly they run into pear-shaped 

 dilatations which open by a common sphinctered terminal ori- 

 fice. These dilatations near the opening are lined by rather 

 high club-shaped epithelial cells. 



The nervous system (PI. XXXIX, Fig. 4) consists of a large 

 commissure running dorsal to the muscular pharynx, and con- 

 necting two ganglionic swellings. From this are given off 

 several small nerves to the anterior extremity, and backward 

 there run four main trunks, two dorsal arising from the com- 

 missure, and two lateral running from the ganglionic swellings 

 ventral to the coeca toward the posterior end of the body. A 

 short distance behind the bifurcation of the intestine these 

 ventral cords give off a branch which runs marginally back- 

 ward. The finer ramifications of these nerves have not been 

 traced. 



We have left for consideration the genital apparatus. The 

 male portion of this apparatus consists of two median testes 

 with their vasa efferentia and a complicated cirrus. 



The testes are large, and situated one behind the other in 

 the median line, the left being anterior ; their outline is not 

 simple, but they tend to be lobulated. The vasa efferentia are 

 wide and dilated at points with spermatozoa ; they unite im- 

 mediately before joining the cirrus sac. The penis (PI. XXXIX, 

 Fig. 3) consists of a long convoluted, rather thick-walled sac 

 filled with spermatozoa, into which the vasa efferentia, or rather 

 the short vas deferens formed by the union of these tubes, opens. 

 This sac runs directly into a narrow, very muscular tube, which 

 shows active peristaltic movements during life. At the end of 

 this there is, apparently, a differentiated portion of the muscu- 

 lature which acts as a sphincter, making a dividing line between 



