146 



Gen. 2. LeptOpllOXUS, (1. 0. Sara, n. 

 Syn: Phoxus, auctorum (part). 



Body much more slender tlian in the preceding genus. Cephalon 

 slightly keeled anteriorly, tip of the hood more or less distinctly curved down- 

 wards. Coxal plates of moderate size and provided at the infero-posteal 

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

 4th pair considerably broader than the preceding ones, and deeply emarginated 

 posteriorly in their upper part; 5th pair with the posterior lobe subtruncated 

 at the tip. Superior antennae much smaller than the inferior; the latter having 

 the joints of the peduncle considerably expanded, and the flagellum in female 

 very short, in male slender and elongated. Mandibles with the molar expan- 

 sion poorly developed, forming an extremely small unarmed lappet, 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 setae. 

 Maxillae about as in the preceding genus. Maxillipeds with the basal lobe 

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

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

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

 nearly quadrangular in form. Antepenultimate pair of pereiopoda having the 

 basal joint considerably expanded; penultimate pair very slender; last pair 

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

 alike in the two sexes, inner ramus very small, spiniform, outer slender, without 

 setse, but with a few tufts of spines. Telson nearly as in the preceding genus. 



Remarks. I have thought it necessary to establish this new genus 

 in order to include the species formerly named by me as Phoxns falcatu*. 

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

 author, has revealed some peculiar characteristics apparently of generic value, 

 overlooked at that time. Thus the structure of the mandibles is very charac- 

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

 maxillipeds. Finally, the uniform appearance of the last pair of uropoda in the 

 two sexes, is a characteristic by which this genus materially differs from all 

 known Phoxocephalidae. Besides the Norwegian species described below, the 

 Phoxus simplex of Sp. Bate seems to belong to the present genus. I have 

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

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

 which seems to agree pretly well in all essential characteristics with the Nor- 

 wegian form, though being evidently specifically distinct. 



