508 



Mr. II. A. Biiylis on 



atrium towards the anterior border of tlie segment, and ends 

 at, or even beyond, tiie middle line. The testes (tig. 4, T.) 

 immber about twenty, and occupy the posterior half of the 

 segment. There is a much-colled vas deferens. The ovary 

 consists of two groups of lobes, the larger group being on the 

 aporal side. Between the two portions of the ovary there is 

 a large rounded receptaculum seminis (tig. 4, R.S.) ; close to 



Fig. 4. 



/?.5. 



MonopyUditim arcticiim ; semi-diagrammatic drawing of a mature 

 segment (from a whole preparation). 



C 5"., cirrus-sac ; G.A., genital atrium; Or., ovary ; i?.*?., receptaculum 

 seminis ; S., shell-gland ; T., testes ; V., yolk-gland j Vg., vagina. 



this is the shell-gland (fig. 4, 6'.), and behind both these the 

 compact yolk-gland (fig. 4, V.). There are only a few ripe 

 segments at tlie posterior end of the strobila. There is no 

 definite uterus, the ova being embedded singly in the paren- 

 chyme. The onchospheres are about 20 jx in diameter. 



Tliis form differs from M. ciyiguUferum (Krabbe) in a 

 number of points, notably in its smaller number of testes, 



