686 THE VOYAGE OF H.M.S. CHALLENGEE. 



describes the species as large, it may be taken for granted that " "08 inch " in his account 

 is a misprint for " '8 inch," equivalent to four-fifths of an inch. There can, I think, be 

 no doubt that the Challenger species is identical with Stimpson's, and though the incised 

 apex of the telson and the palp on the mandible set far behind the molar tubercle are 

 features that will not agree with Boeck's definition of Lysianassa, I think that Spence 

 Bate rightly referred this S23ecies to that genus. It is the definition of the genus that 

 must be modified, not the species that ought to suffer exclusion. 



Genus Lepidepecreum, Bate and Westwood, 1868. 



For the original definition of the genus, see Note on Bate and Westwood, 1868 

 (p. 373); now that the genus is somewhat better known, it may be defined as follows : — 



Upper Antennw with the secondary appendage small or rudimentary. 



Loiver Antennse with the third joint comj^aratively long. 



Mandibles with the palp narrow, set well behind the dentate molar tubercle. 



First Maxillw. — Inner plate not elongate, carrying two plumose setae at the apex ; 

 outer plate with one of its eleven dentate spines standing a little apart from the rest ; 

 the palp carrying several little spine-teeth and one spine on the truncate apex. 



Second Maxill^e.—The outer plate a little longer than the inner, hoih plates rather 

 narrow and elongate. 



Maxillipcds. — Outer plate with a few nodulous teeth on the inner margin, the plate 

 reaching beyond the rather short second joint of the palp ; the fourth joint of the palp 

 ending in a sharp nail. 



First GnatJiopods not robust, hand and wrist subequal in length, hand subcheli- 

 form. 



r 



Second Gnathopods with the hinder margin of the hand outdrawn. 



Telson more or less cleft. 



There is only the minute rudiment of a secondary appendage on the upper antennae 

 of the type species of Lepidepecreum. A small and two-jointed appendage is figured 

 for Lysianassa umbo, Goes, which Boeck calls Orchomene umbo, but which G. 0. Sars 

 would refer to Lepidepecreum. The species here referred to that genus has numerous 

 points of similarity with the species described by Goes. 



Lepidepecreum foraminiferunfi, n. sp. (PI. XXIV.). 



A small rostrum ; lateral lobes of the head outdrawn, very long and narrow ; the 

 whole animal dorsally sharply ridged from one end to the other, on the last two segments 

 of the peraeon and first three of the pleon the ridge forming a distal tooth ; the lower 



