146 



Gen. 2. LeptophoXUS, (1. 0. Sars, n. 

 iSyu : Phoxus, auctorum (part). 



Body mucli more slender than in tlie preceding geniis. C'ejilialon 

 sliglitlv keeled anteriorly, tip of tlie liood more or less distinctly curved down- 

 wards. Coxal plates of moderate size and provided at tlie infero-pnsteal 

 corner witli a few simple bristles; 1st pair more or less expanded distally ; 

 4tli ]iair considerably broader than the preceding ones, and deejily emarginated 

 posteriorly in their iipper ])art; ntli pair with tlie posterior lolie snlitrnncated 

 at the tip. Superior antenna^ much smaller than tlie inferior; the latter having 

 the joints of tlie peduncle consideralily expanded, and the tlagellum in female 

 very short, in male slender and elongated. Mandildes with tlie molar expan- 

 sion poorly developed, forming an extreniel_^- small unarmed lajipct, palp very 

 large with the 2 outer joints laminarly expanded, the last widening distally 

 and provided on the transversely truncated tip with a series of curved setse. 

 Maxillse about as in the jireceding genus. Maxillipeds with the basal lobe 

 very small and acuminate at the tip, penultimate joint of the jialp more or 

 less produced at the outer corner. (Inathopoda very unequal in size, the 

 posterior ones being much more powerful than the anterior, hand in both 

 nearly (juadrangular in form. Antepenultimate pair of pereiopoda having the 

 basal joint considerably expanded; penultimate pair verj' slender; last pair 

 with the basal joint large and clypeiform. Last pair of urojioda exactly 

 alike in the two sexes, inner ramus very small, spiniform, outer slender, witliout 

 seta", but with a few tufts of spines. Telson nearh' as in the preceding genus. 



I{rmarls. — I have thought it necessary to establish this new genus 

 in order to include the species formerly named by me as Phoxus fnlcafiis. 

 The closer anatomical examination of this form, subsequently instituted by the 

 author, has revealed some peculiar characteristics apparently' of geneiic value, 

 overlooked at that time. Thus the structure of the mandibles is very chai'ac- 

 teristic, as also the peculiar form of the penultimate joint of the palp of the 

 maxillipeds. Finall}', the uniform appearance of the last pair of urojioda in the 

 two sexes, is a characteristic bj- whicli this genus materiall}' differs from all 

 known Phoxoceiihalidge. Besides the Norwegian species described below, the 

 Phoxus smi2)lex of Sp. Bate seems to belong to the firesent genus. I liave 

 received from Dr. Chevreux specimens of a small species from the Frencli 

 coast, wliicli I believe is identical with the above-named British form, and 

 which seems to agree pretly well in all essential charactei'istics with the Nor- 

 wegian form, though being evidently specifically distinct. 



