164 CLASS CRUSTACEA. 



upon themselves, with the fingers abruptly bent, and forming 

 an angle ; ocular pedicles very short, and not at all, or very 

 little projecting from their cavities, and a shelly testa, very 

 unequal, or very spiny, characterize 



Parthenope, Fab. 



Some of them have the lateral antennae very short, of the 

 length of the eyes at most. Their first articulation is entirely 

 situated below the ocular cavities. 



If the tail presents in both sexes seven segments, these spe- 

 cies will compose Parthenope, properly so called, of Dr. 

 Leach. If those of the males present but five, we shall have 

 his genus hamhrus. 



The others have the lateral antennae very sensibly longer 

 than the eyes. Their first articulation is prolonged as far as 

 the internal upper extremity of the cavities proper to these 

 last organs, and appears to be confounded with the testa. 

 Here the post-abdomen always consists of seven segments. 

 The claws of the females are much shorter than those of the 

 other sex. The same naturalist distinguishes generically 

 these Crustacea under the denomination of jE'2«rywow«. (Can- 

 cer asper Pennant.) 



In the following the claws are always advanced, and their 

 length is at most double that of the body. Their fingers are 

 not abruptly and angularly inclined. 



Here the length of the longest feet (the second pair) little ex- 

 ceeds that of the testa, measured from the eyes to the origin of 

 the tail. The under part of the tarsi is generally either den- 

 ticulated or spiny, or garnished with a fringe of hairs, termi- 

 nating like a knob. 



We shall present, in the first place, those whose ocular 

 pedicles are very short, and of middle length, capable of 



