The heart is rather small, exhibiting the usual structure. 



The ovaries are often very large and filled with a clear 

 greenish substance. 



The ova recently discharged into the matrix still retain this 

 colour, at least in the centre, but very soon, as the development 

 of the embryo proceeds, assume an orange and finally a reddish 

 tint. Their number is often very great. 



The colour of the adult animal varies somewhat, according 

 to age, being at first rather pale yellowish, changing to orange. 

 In older specimens the body often assumes a more or less bright 

 reddish hue, whereas the shell itself generally retains its clear 

 orange colour and pellucidity. 



The adult male (fig. 5) is very small, scarcely half the size 

 of the old female, and at first sight somewhat resembles female 

 specimens when quite young and not yet sexually developed. On 

 closer examination, however, it may readily be recognized by a 

 somewhat different form of the carapace, which is more oblique 

 and always exhibits several lines of growth, not yet present in 

 equal-sized female specimens. Moreover, it is easily distinguished 

 by the much larger size of the antennulse, which are consider- 

 ably dilated in the middle and provided anteriorly with a very 

 conspicuous bristle, wanting in the female. Finally, the eye is 

 somewhat larger and located nearer the front than is the case 

 in female specimens. It is very remarkable, however, that the 

 1st pair of legs, which, as is well known, are generally much 

 modified in the males, neither in this nor in any other species 

 of the present genus, exhibit the slightest difference from those 

 in the female, being as in the latter very small and wholly de- 

 void of the usual anteriorly curved claw, a fact perhaps to be 

 accounted for by the slow movements of these animals, making 

 it less necessary for the males to get a faster hold of the females 

 during copulation. The testes may be readily distinguished 

 through the shell as 2 elongate saccular organs extending along 

 the sides of the intestinal tube and filled with an opaque whitish 

 substance; they would appear to have their outlet at the tip of 



