207] PROTEOCEPHALIDAE—LA RUE 207 



cirrus-pouch is more slender than in several other species of Ophiotae- 

 nia. In mature and ripe proglottids it measures from 0.255-0.320 mm. 

 long by 0.08-0.09 mm. broad. In maturing proglottids it measures 

 about 0.25 mm. long and is considerably narrower than in ripe ones. 

 Its length goes into the proglottid breadth 3-4 times. In mature and 

 ripe proglottids the vagina very near its opening to the exterior has a 

 wide but short inflated region. A sphincter vaginae has been found. 

 In this region the vagina is richly set with gland cells. In its course 

 to the interovarial space the vagina bends somewhat anteriad and then 

 inward and posteriad, crossing the numerous coils of the vas deferens 

 but not crossing the cirrus-pouch. Just before the ovary is reached the 

 vagina is somewhat twisted or even thrown into small coils. A small 

 receptaculum seminis can be seen in some preparations. The ovarian 

 lobes are long flattened bodies of irregular outline. They are not solid 

 but are made up of short heavy anastomosing tubes of irregular shape. 

 Just back of the mid-piece of the ovary the muscular oocapt can be 

 noted even in toto mounts. The coils and connections of the oviduct, 

 vitelline duct, uterine passage and lower vagina cannot be made out 

 distinctly. An ootype and shell-gland have been seen in some prepara- 

 tions. 



The vitellaria are loosely follicular and lateral. The paired vitel- 

 line ducts cross the ovarian lobes. The uterus in maturing proglottids 

 is a median tube from which as the proglottid becomes older lateral 

 pouches arise by the method that has been described for O. filar oides 

 by La Rue (1909). There are 20-30 large pouches on either side and 

 a number of smaller ones. No uterine pores have been seen. In one 

 toto preparation the uterine passage may be traced to a point 0.29 mm. 

 anterior to the mid-piece of the ovary where it discharges into the 

 uterus. 



The eggs are furnished with three membranes, an outer one which 

 is smooth, thin and hyaline, a middle membrane thick and granular, 

 and an inner thin membrane surrounding the embryo. The outer 

 spheroidal membrane measures 0.045-0.06-0.100 mm. and the embryos 

 are 0.018-0.021 mm. in diameter. Plerocercoids were found encysted in 

 the intestine and liver of the host caught at Havana, Illinois. 



This species is much smaller than Crepidobothrium gerrardii 

 (Baird), O. marenzelleri (Barrois), O. calmettei (Barrois) and O. tri- 

 meresuri (Parona) in most respects tho it may exceed some of these in 

 length. It most closely resembles O. nattereri (Parona), likewise from 

 one of the Colubrinae. It has a larger head and larger proglottids and 

 a greater number of testes than O. nattereri. O. perspicua is much 

 larger than 0. filaroides La Rue from Amblystoma tigrinum Green. Its 



