fjAM.MARll).E. oJi 



3. Nicea Prevostii. 



Ainphitoe Prevostii, Udtvanh, Ann. des Sr. Nat. t. xx. p. 378, and 

 ser. 2. t. iii. pi. 14. tig. 11 ; Ilist. ck-s CruM. t. iii. p. -30. 



' • Cepluilou without a rostrum. Superior antennae very short, scarcely 

 passing the peduncle of the inferior ; inferior antennae also short, 

 having about fourteen joints to the flagelluni. Eyes oval. First 

 pair of gnathopoda haWng the propodos ovate, not dontated, and 

 not longer than the carpus. Second pair of gnathopoda havdng 

 the propodos very large ; palm nearly straight, and armed with 

 spines ; in the female the propodos is not so largely developed ; 

 dactylos veiy large, and, when closed, forming with the propodos 

 an oval. The last two segments of the pleon are rudimentaiy ; the 

 pleopoda which they support are shorter than those of the fourth 

 segment. Telson two little, short and obtuse stylets. 



'' Hah. The Gulf of ^Q.])\csr—MUne-Eilivarcls. 



Upon examining the typical specimen in the Museum of the Jardin 

 des Plantes, I came to the conclusion that it was synonymous with 

 NUssonii of Rathke, but unfortunately omitted to observe the cha- 

 racter of the telson. Edwards states it to consist of two little, short 

 stylets, — a circumstance which compels me to arrange it under Nicea 

 rather than with AUorchestes, with which in all other respects it 

 appears to be identical. 



Tribe Natatoria. 



The superior antennae never rudimentary. The posterior pair of 

 pleopoda reaching to the extremity of the preceding. The hairs 

 upon the entire animal are generally slight and flexible. 



The habits of the animals are aqimtic. Their common mode of pro- 

 gression, when in the water, is by swimming or walking ; and when 

 accidentally removed from that element, they wriggle along upon their 

 side — a circumstance that has obtained for them the familiar name 

 of '•' Sea-screws." This tribe, like that of Saltatoria, contains but 

 one family. 



Fam. 2. GAMMARID^. 



Superior anttJnnoe well developed. The inferior antennae inserted 

 in a notch at the infero-anterior angle, and not fused with the 

 cephalon. Maxillipeds unguiculatc. The coxte largely developed 

 and s(|uamiform. 



This family is made up of several subfamilies, which differ from each 

 other in more or less important points. 



