MYSIDEA. 605 



divergent, shoulders not armed. Abdomen very slender; caudal 

 segment linear, emarginate at apex, and having a minute spine 

 near middle of sides. First antennae slender, first joint twice longer 

 than the eyes. Posterior feet nearly half shorter than next pre- 

 ceding, palpus two-jointed. 



Plate 44, fig. 6, animal, enlarged. 



Pacific, thirty miles west of Assumption Island, one of the Ladrones. 

 Collected, December 30, 1841. 



Length, one-eighth of an inch. Colourless. The carapax is very 

 much broader than in the armata, and but little contracted anteriorly, 

 and, moreover, the front angles are slightly divergent ; length of cara- 

 pax, not twice its greatest breadth. The emargination at apex of last 

 abdominal segment is rounded ; each side of the same segment has a 

 minute spine near middle, and quite near the apex there is a second 

 lateral spinule ; at apex there appeared to be six spinules. The 

 branches of the thoracic legs are few-jointed; only two or three 

 joints are given in the drawing made from the living animal, and 

 they are furnished with a few setee. The outer antennae of the speci- 

 men were broken. 



SCELETINA ORIENTALIS. 



Carapax anticd constrictus, perangustus, cuspidibus lateralibus parce 

 divaricatis, Jiumeris armatis. Segmenta abdaminis sex processu acuto 

 infra utrinque armatum; Qtum longum, infra unispinosum ; septi- 

 mum fere lineare, apice truncate el spinulis sex armato, lateribus cum 

 duabus spinulis minutis armatis. Pedum palpus apice minute* arti- 

 culatus. 



Carapax constricted and very narrow in front, anterior acute angles a 

 little divaricate, shoulders armed. Six abdominal segments pro- 

 vided below on either side with an acute process or spiniform tooth ; 

 sixth long and with a tooth below ; last segment nearly linear, apex 

 truncate and set with six spinules, each lateral margin with two 

 spinules. Palpus of feet having minute joints at apex. 



167 



