147 

 2. Leptophoxus falcatus, &. 0. Sars. 



(PI. 60). 



Pho.rus falcatus, G. 0. Sars, Oversigt af Norges Crustaceer I. p. 84. 



Syn : Phoxus simplex, Boeck (not Sp. Bate). 



Body very slender and compressed, especially in the male. C'ephalun 

 exceeding the length of the 3 anterior segments of mesosome combined, hood 

 distinctly carinated along the middle and terminating with a hook-like deflexed 

 ]inint. The 3 anterior pairs of coxal plates each with 3 small bristles at the 

 infero-posteal corner; 1st pair considerably expanded in their oiiter part, distal 

 edge arched; the 2 succeeding ones regularly qiiadrangular ; 4th pair much 

 liroader than the preceding ones, and transversely truncated posteriorly, upper 

 angle nearly right ; 5th pair with the posterior lobe slightly expanded and 

 ol^tusely truncated at the tip, upper angle rather projecting. Last pair of 

 ejumeral plates of metasome with the posterior edge considerably arched, 

 lateral corners obtuse. Eyes wholly absent. Siiperior antennae, much .shorter 

 than the cephalon, 1st joint of the peduncle rather thick and considerably 

 exceeding the length of the other 2 combined, flagellum about the length of 

 the jieduncle, and composed of 5 articulations, accessory appendage scarcely 

 lialf the length of the flagellum, and 3-articulate. Inferior antennae in female 

 nearly twice the length of the superior and more or less strongly curved, 

 the 2 outer joints of the peduncle armed anteriorly with tufts of slender 

 spines, and posteriorly with a few ciliated setae, flagellum scarcely half the 

 length of the' peduncle, and 5-articulate ; those of male not fully attaining the 

 length of the body. Penultimate joint of the palp of the maxillipeds pro- 

 duced at the outer corner to a narrow conical process tipped with 4 ciliated 

 setae. Gnathopoda rather powerful, hand of the anterior ones narrow quadran- 

 gular, that of the posterior nearly twice as large, and subquadrate in form, 

 thumb-like process in both rather projecting. Antepenultimate pair of pereiopoda 

 with the basal joint fully as broad as it is long, posterior edge evenly arched; 

 ]ienultimate pair nearly attaining half the length of the bod}^ ; last pair with 

 the basal joint rather large, though not attaining the length of the remaining 

 part of the leg, posterior edge obliquely arched, and exhibiting a few slight 

 serrations. The tii'st 2 pairs of uropoda with both rami slender, mucroniform 

 and quite naked; last pair projecting considerably beyond the preceding ones, 

 inner ramus extremely small, the outer slender, with the terminal joint very 

 narrow and about half the length of the basal one. Telson slightly dilated 

 in the middle, each lobe tipped with a single spine and a small Ijristle. 

 Body whitish, pellucid. Length of adult female 4mm; of male about the same. 



Beniarks. — The present easily recognizable form, which was errone- 

 ously identitied by Boeck with Phoxus simplex Sp. Bate, is at once distinguished 



