28 
The so-called shell gland (s. g., ligs 32, 33) has the usual position 
between the ovar}" and yolk gdand, on the dorsal side of the latter. 
It is composed of only a few cells, and is very small and insignificant. 
It must not be imagined that this tiny complex of a few small cells 
Fig. 32. — Cross section of proglottid of H. nana from man: c. p., cirrus pouch; cort. par., cortical par- 
enchyma; ex. can., excretory canal; m. 1. n., main lateral nerve; ov., ovary; rec. sem., receptaculum 
seminis; s. g., shell gland; t, testis; y. g., yolk gland. Enlarged. (After Linstow, 1896a, .fig. i.) 
produces the material out of which the shells of the hundred or more 
eggs, contained in the gravid segment, are formed, which is a clear 
impossibility, since a single egg with its full}^ formed shell is much 
larger than the entire shell gland. The function of the shell gland in 
tapeworms in general has never been satisfactoril}- explained. 
Fig. 33. — Cross section of proglottid of II. nana from rat. Lettering as in fig. 32. Enlarged. (After 
Linstow, 1896a, fig. 1.) 
The uterus (fig. 23) develops veiy rapidl}- after sexual maturity is 
reached, the ovary disappears, and all the other organs, except the 
seminal receptacle and the cirrus pouch, degenerate completely or are 
masked and crowded out of sight by the uterus and its contained 
embryos. The uterus in the oldest segments occupies practically all 
cort par. 
\Ln. 
ex. can. 
rec. sem. 
