HYMENOCERA. CRUSTACEA. 167 



G. elegans, Lat. (Alpheus, Risso.) Body oblong, gibbous, arched 

 towards the third joint of the abdomen ; shell smooth, terminat- 

 ed before by a small compressed rostrum, dentated above ; laci- 

 niae of the tail ciliated and white ; last segment of the abdomen 

 violet. Inhabits Mediterranean sea. Desm. Crust. 228. 



Gen. 65. HYMENOCERA, Lat. 



Intermediate antennae bifid, with the upper division foliaceous ; 

 exterior feet-jaws foliaceous, covering the mouth ; four an- 

 terior feet terminated by a didactyle foliaceous hand. 



This genus was instituted by Latreille for a new species from the East Indies. 



Gen. 66. NIKA, Risso. Processa, Leach. 

 Intermediate antennae terminated by two setaceous filaments ; 

 the exterior ones setaceous, long, with an elongated scale at 

 the base, unidentate exteriorly, and ciliated on the internal 

 margin ; exterior feet-jaws not covering the mouth ; feet ge- 

 nerally slender and long, of unequal size, each with a small 

 didactyle hand ; abdomen bent towards the third segment, 

 terminated by foliaceous laminae. 



N. edulis, Risso. Shell very smooth, terminated by three sharp 

 points, of which that in the middle, or the rostrum, is the long- 

 est ; colour bright red, dotted with yellowish, and a line of small 

 spots in the middle ; eyes green. 1^ inch long. Inhabits Medi- 

 terranean sea. Risso, Crust, pi. 3. 



Gen. 67. PAL^MON, Fab. Cancer, Lin. Astacus, Pen. 

 Intermediate antennas formed of three filaments, two long and 

 setaceous, and one short and thick ; lateral ones longer than 

 the body ; four anterior legs didactyle ; anterior smaller than 

 the second pair ; exterior feet-jaws with the last joint shorter 

 than the preceding ; shell thin, elongated cylindrical, termi- 

 nated before by two sharp lateral points, and a very long ser- 

 rated rostrum. 



P. serratus, Leach. The Common Prawn. Rostrum ascending, 

 prolonged, with from 6 to 8 teeth, the apex emarginate ; below 

 with from 4 to 6 teeth ; colour pale red. 3 to 4 inches long. 

 Coasts of Britain and France. Penn. Brit. Zool. iv. pi. 17, fig. 1. 



P. squilla, Leach. Rostrum shorter than in the preceding, notched 

 at the end, with seven or eight teeth above^ and three below ; toes 

 shorter than the hand. Inhabits coasts of England and France. 

 Lin. Trans, xi. 348. 



Gen. 68. ATHANAS, Leach. Cancer, Mont. 

 Four anterior legs didactyle ; anterior pair larger than the se- 

 cond ; exterior feet-jaws with the last joint longer than the 

 preceding ; thorax cylindrical, narrower before than behind ; 

 exterior laminae of the tail of three pieces. 



