;}42 AMl'lllPODA NOKMALIA. 



2. Synopia angustifrons. (Plate LIV. fig. 2.) 

 Synopia anguatifrons, Dana, U. S. U!xj)l(»: Exped. p. 998. pi. GS. f. 8. 



" Similar to the 8. nltramarhia. Cophiilon very narrow, the sides 

 converging forward at an angle of 40° to 45°. Inferior antenna? 

 considerably shorter than the body ; flagellum consisting of ten 

 articuli ; articuli slender, cylindrical : superior pair but a little 

 longer than base of inferior ; flagellum consisting of five articuli. 

 Second pair of pereiopoda having the cai-pus straight along the 

 anterior, and arcuate on the opposite margin ; propodos and dactylos 

 slender, and nearly equal. 



" Length -ith of an inch. 



" Hab. Pacific, in latitude 18° S., longitude 122° W. Collected 

 August 1S39."— Dana. 



Subfam. 2. OXYCEPHALIDES. 

 Having the eyes situated posteriorly to the superior antennae. 



2. OXYCEPHALUS. 



Oxyceplialus, Edwards, Ann. des Sc. Nat. xx. p. 396} Hist, des Crust. 

 iii. p. 99. 



Body long and slender. Cephalon produced anteriorly. Antennoe 

 situated on the inferior siu-face. Gnathopoda complexly subche- 

 late. Two anterior pairs of pereiopoda simple ; two succeeding 

 having the basa dilated ; the posterior diminutive. Three poste- 

 rior pairs of pleopoda double-branched ; rami lanceolate. Telson 

 squamiform, triangular. 



1. Oxycephaliis piscator. (Plate LIV. fig. 3.) 



Oxyceplialus piscator, Edwards, Ann. des Sc. Nat. xx. p. 39G ; Hist. 

 des Crust, iii. p. 100. pi. 30. f. 10. 



" Cephalon as long as the first five segments of the pereion, tolerably 

 broad, not narrowed behind the eyes, terminating anteriorly in 

 a long triangular rostrum. Eyes oceupj^ng all the middle and 

 posterior portion of the cephalon. Superior antennae bent in the 

 form of the letter Z ; first three joints [pedtincle] la.rge, compressed, 

 and furnished with a number of hairs ; last three [flagellum] 

 small. Inferior antenna? large, and having the same form as in 

 Thyropus ; but the four joints are subequal, the last being uni- 

 articulate. First pair of gnathopoda shorter than the second ; 

 propodos very large, compressed, and with spines upon the infe- 

 rior margin ; dactylos not \ery distinct. Second pair of gnatho- 



