24 G- O. Sars. 



In form (see Pl. V, figs. 1, 2), the shell looks exactly 

 like that of the female, and has the dorsal margin 

 curved in the very same manner, so as to be scarcely 

 distinguishable from that of young female specimens. It 

 is therefore only by examining the enclosed animal that 

 the sex is to be ascertained. 



Fig. 3 on the same plate represents, more highly 

 magnified, the whole animal extracted from the shell, and 

 viewed from the left side. As shown by the figure, the 

 male character of the individual is at once revealed by the 

 peculiar structure of the 2 anterior pairs of legs, which 

 are both transformed into strong grasping organs. They also 

 both exhibit a very strong curvature, and are extended 

 somewhat apart from the other legs, being applied with 

 their proximal part against the löwer face of the anterior 

 division of the body. On a closer examination, some 

 other well-marked differences from the female may also be 

 found to exist. 



Thus, the rostral expansion of the head (fig. 4) is of 

 a very different appearance, being produced to a rather 

 prominent, triangularly pointed projection. 



The antennulæ (ibid, and fig. 5) are much more fully 

 developed than in the female, equalling the head in length. 

 In the specimen examined, they were extended straight 

 behind between the bases of the 2 anterior pairs of legs, 

 whereas in the female they are, as a rule, found pointing 

 downwards. As, however, these limbs are to a certain 

 extent movable, their direction may, in the living animal, 

 admit of being changed. The lobules of the terminal part 

 appear much more sharply defined than in the female, and 

 are very densely clothed with olfactory papillæ (see fig. 6). 

 They are about 9 in number, and between them, faint 



