385] .1X0PL0CEPHALIDJE—D0UTHITT 35 



the ventral system in these cases, and the connection with the ventral 

 system appears secondary. This effect is heightened by another re- 

 markable feature, the presence of a secondary transverse commissure 

 anterior to the first. This duct is a direct continuation mediad of the 

 longitudinal ventral duct at the point where the latter dips distad just 

 before communicating with the main transverse commissure. This sec- 

 ondary duct is usually of small diameter dorsoventrally but antero- 

 posteriorly it may extend through one-fourth the length of the pro- 

 glottid. Its diameter however is very irregular, and its course is sinu- 

 ous. These secondary commissures are apparently analogous to the 

 condition found in 8. anoplocephaloides. The connections between dor- 

 sal ducts and transverse commissures were observed also in S. anoplo- 

 cephaloides, and by Stiles in S. americana. In two proglottids the main 

 transverse commissures are not fully developed, but are represented by 

 strings of disconnected spaces. This may be due however to the fact 

 that the proglottids are not quite mature. All these conditions are 

 illustrated in Fig. 31. 



Schizotaenia anoplocephaloides sp. nov. 



[Figures 33 to 40] 



Four gophers (Oeomys oreviceps Baird) from creek bottom land 

 at Norman, Oklahoma, yielded of this species plentifully. About half 

 of the 75 specimens taken were lost and tho many others are not in the 

 best condition, some are good. For distribution and frequency of this 

 species see the table on page 62. 



The total length of the specimens at hand is 30 to 33 mm. The 

 number of proglottids varies from 55 to 80, the average being 68. 

 There is no neck. The first proglottids are about seven-tenths the 

 diameter of the scolex and from one-eighth to one-twelfth as long as 

 broad. The maximum width of 1.7 to 2 mm. is reached about the 

 middle of the strobila ; back of this the width remains constant or 

 decreases slightly. At the middle of the strobila the proglottids are 

 from one-fifth to one-third as long as broad. They increase in length as 

 they become older, becoming finally two-thirds as long as broad. In 

 those proglottids in which the eggs are being fertilized the large 

 everted genital pore protrudes prominently. 



The scolex averages 390/x in diameter and 320/j, long and is quite 

 distinct from the strobila. It is clearly separated into anterior and 

 posterior portions by a slight transverse constriction near its middle. 

 The apex is blunt, the anterior outline being a regular curve. The 

 scolex is rather deeply four-lobed owing to the presence of longitudinal 



