4 
Hymenolepis longior n. sp. 
positions with regard to the ovary. The three testes are relatively much 
smaller than in H. nana and H. nana fraterna, and, instead of being almost 
equal in diameter to the antero-posterior length of the segment, they occupy 
only a small space close to its posterior border. They are generally more 
oval in shape than those of the other species, which are almost spherical. 
Their greatest diameter varies from 0-05 to 0-075 mm. The middle testis varies 
e. 
c.s. 
n. 
Fig. 3. Hymenolepis longior. Three mature segments; dorsal view. (From a whole preparation.) 
c.s., cirrus-sac, with contained internal seminal vesicle; e., excretory canals; n., longitudinal 
nerve; oy., ovary; r.s., receptaculum seminis; s., shell-gland; t., testis; v., vitelline gland; 
v.s.e., external seminal vesicle. 
01mm. 
Fig. 4. Hymenolepis nana fraterna. Two mature segments; dorsal view. (From a 
whole preparation.) Lettering as in Fig. 3. 
in position with regard to the yolk-gland, and may lie dorsally to it or on 
either side of it. In the other species it seems to be always in the centre of 
the segment and dorsal to the yolk-gland. The genital pore is situated at about 
the middle of the lateral border of the segment, or very slightly in front of it. 
The cirrus-sac, which measures about 0-15 mm. in length, passes, as usual in 
Hymenolepis, dorsally to both the longitudinal excretory vessels and to the 
