NEW SPECIES OF IIYMEXOLEPIS. 



241 



O.018-0.02 mm. It is always shorter than half the breadth of the 

 segment. The proximal broad parts contain an oval dilatation of the 

 lumen, which probably serves as the second seminal vesicle. (Figs. 

 13-15). 



Female reproductive organs. —Ovary, yolk-gland and shell-gland 

 form a co npact massin the median ventral side, in which the said 

 several glands can not be clearly distinguished. From that mass a 

 winding duct passes laterally to the seminal receptacle, situated on the 

 ventral side of cirrus pouch. The seminal receptacle (sr) is ovoid or 

 spherical, 0.03-0.05 mm in diameter, and looks very much like the 

 seminal vesicle. In consecutive ripe segments the receptacles form a 

 series of dots along the porose side, presenting a very characteristic 

 appearance (fig. 12. A, B). 



The vagina runs in a nearly straight line from the seminal 

 receptacle. It opens externally directly behind the male opening by 

 a pore, which is too small to be easily observed. (Figs. 23 & 14, vg.). 



Onchospheres contained in posterior segments measure 0.05 mm. 

 in diameter (fig. 16). 



Musculature. — The muscular system is very weakly developed. 

 There exists only a single layer of longitudinal muscles which are so 

 thin as to readily escape observation. 



3. Hymcnolepis trichorhynchus n. sp. 

 Pl. VII., figs. 17-25. 



This new species was obtained Febr. 15, 1906, in numerous 

 quantity from the duodenum of common teal (Anas crecca L.) killed 

 in Tokyo or in the neighborhood. 



Diagnosis. 



Length 4-4J mm. Slender in the anterior parts, much broader in 

 the posterior. Rostellum long and thin when fully extended, with a 

 circle of 10 hooks (0.04 mm. long) before evagination. Rostellum sac 



