THE CRUSTACEA OE NEW JERSEY. 207 



peculiarly modified to adapt them for semi-parasitic life. 

 Gnathopoda rather unequal in structure, usually feeble and an- 

 terior ones always extremely slender, often showing- an approach 

 to cheliform character. Perseopoda normal, basal joint of three 

 posterior pairs laminarly expanded. Last pairs of uropoda with 

 rami narrowly lanceolate and edged with minute denticles. Tel- 

 son unarmed, slightly incised at tip. 



Genera three, represented in northern seas. Some are said 

 to be parasitic and others are thought to be semi-parasitic. 



Genus ACANTHONOTOZOMA Boeck. 



Acanthonotozoma Boeck, Island. Amphip., 1876, p. 237. Type Acanthonoins 



cristatus Owen, designated, first species. 

 Acanthonotosoma, Acanthostoina, auct. 

 Acanthonotus (nee Schneider 1801) Owen, Append. Second Voy. Ross, 18.33, 



p. 90. Type Acanthonotus cristatus Owen, monotypic. 

 Vertumnus (nee Otto, 1821) (Leach) White, Cat. Crust. Brit. Mus., 1847, p. 



89. Type Vertumnus cranchii White, monotypic. 



Body more or less compressed, distinctly carinated dorsally. 

 and carina usually elevated to posteriorly pointing projections. 

 Cephalon with rather large rostrum evenly curved downwards, 

 lateral corners small. Three anterior pairs of coxal plates rather 

 narrow, tapering to a point. Eourth pair considerably larger 

 and securiform in shape, outer part triangularly pointed. Two 

 succeeding pairs moderate in size, with posterior lobe deeper 

 than anterior. Eyes comparatively small. Superior antennae 

 with peduncle rather elongated. Anterior lip narrowly pro- 

 longed and minutely incised at tip. Posterior lip with lobes 

 narrow'ly produced. Mandibles rather elongated, cutting part 

 narrowly projected, very narrow accessory lamella on both 

 mandibles, molar expansion obsolete, and palp slender. First 

 pair of maxilte with masticatory lobe very obliquely truncated 

 at tip, armed with short denticles, basal lobe triangularly pointed 

 and with numerous short setae on inner edge, palp comparativelv 

 small. Second pair of maxillae with outer lobe much larger 

 than inner, obliquely truncated at tip. Maxillipeds with broad 

 basal part laminar, basal lobes nearlv of same size as masticatorv 



