in detail (fig. 2). They each form a slender tube extending through the exposed 

 part of the trunk in close juxtaposition to the intestine. At the anterior extre- 

 mity, which, unlike what is often the case with the ovaries, never penetrates the 

 part of the body-cavity covered hy the carapace, 4 small cereal lobes are seen 

 outside. These lobes, in the genus Lr.ucon (tigs. 2, 3), arc \rry short and 

 somewhat unequal in si/.e. whereas in D'taxli/H* (figs. 12, 13) they are more 

 prominent, almost digitiform, and of about equal size. They contain the germinal 

 stratum of cells, from which the zoosperms are developed, the tube itself being 

 tilled with densely crowded bundles of fully developed zoosperms. whereby it 

 acquires a closely striated appearance. Behind, each tube contracts to a narrow 

 duct, which in the last pedigerous segment curves abruptly downwards, debouching 

 on the ventral face of the latter at the tip of 2 small juxtaposed prominences 

 (see fig. 2). The zoosperms are of considerable size and arranged in dense 

 bundles, each bundle being developed from a single germinal cell and containing 

 about a dozen zoosperms. At first the bundle is enveloped by a thin membrane 

 (see fig. 4); but this soon becomes ruptured. The zoosperms, however, still 

 remain tied together in bundles (see fig. 5), and it is only after being evacuated 

 from the body that they separate. Each zoosperm (see figs. 7 11. 14 16, 

 22) consists of 2 unequal parts uniting at an acute angle. The smaller part is 

 of very delicate structure, and exhibits traces of a nucleus at its base. It varies 

 somewhat in form in different Cumacea, being sometimes lanceolate in shape 

 (figs. 9 11). sometimes more thread-like (figs. 7 8, 14 16), and in some cases 

 distinctly twisted (fig. 22). When not fully developed, this part is curled up in 

 a close coil, as found in young male specimens of Diastylis (figs. 17 20). It 

 seems to represent the essential part of the zoosperm, answering to the so-called 

 head in zoosperms of the usual form. The larger part of the zoosperm, answering 

 to the tail, has the form of a slender elastic seta, several times as long as the 

 above-mentioned part, and terminating in a very fine point. 



