and on Six New Species of Cruntacce^ Sf^e. 18^ 



mentioned, the thorax apparently becomes much smaller ; 

 this arises from the contents of the sac escaping, and the tho- 

 rax proper only being left. The head is separated from the 

 body by means of a slight constriction. The eyes are very 

 large, reticulated, and black ; they are situated on the dorsum 

 and anterior part of the head, on two round tubercles (fig. 15, 

 PI. III.) there being a notch on the mesial line. These tu- 

 bercles, I have no doubt, form the ocular footstalks, when the 

 animal has come to maturity. The carapace is about twice 

 the length of the head, its free or lower edge falls considera- 

 bly down, concealing the origins of the legs ; at this part the 

 thorax is quite transparent, the extreme edge being only of a 

 red colour. Immediately below the eyes are the four anten- 

 nas ; the inferior pair arise from the lower surface of the body, 

 and the first articulation, or what may be termed the pe- 

 duncle, just reaches the anterior edge of the carapace; it then 

 gives off two articulated setae, which are considerably longer, 

 very transparent, and taper to exceedingly fine points. The 

 superior antennae, which are also the innermost pair, are 

 more robust, the peduncle is longer than that of the infe- 

 rior one ; this pair of antennas act much in the same way as 

 the inferior, only the setae arises from the superior edge of 

 the peduncle. Four legs arise from the posterior part of the 

 thorax ; they are bifid to the first like the antennae. The ab- 

 domen is seven-jonted, about three times as long as the tho- 

 rax, the last joint spoon-shaped, the lower surface being con- 

 cave. The posterior edge is armed with a single fringe of 

 strong spines, ten in number ; it is notched in the centre. 

 (Fig. 14, Plate II.) 



This discovery of a metamorphosis will enable us to decide 

 with greater precision on the species of Crustacea, the larvae 

 of these animals having specific distinctions as decided, doubt- 

 less, as those of the insecta. 



SECTION IV. 



On the Structure and Habits of the CapreUce ; with descriptions of 

 some new Species. 



The genus Caprella of Lamarck was separated by Latreille 

 from the Isopoda, with a number of other crustaceous animals, 



