256 REPORT OF NEW JERSEY STATE MUSEUM. 



Body oval or oblong, distinctly depressed, coxal plates beyond 

 first segment well defined, laminar. Cephalon snbquadrate, lat- 

 eral parts not expanded. Metasome with three short segments 

 exposed in front of terminal one, third segment less perfectly 

 defined dorsally. Eyes lateral, distinct. Superior antennae with 

 short clavate flagella. Inferior antennae with mostly elongated 

 multiarticulated flagellnm. Mandibles very strong, cutting-edge 

 divided in two superposed dentated lamelLx, molar expansion 

 large and thick. Both pairs of maxillae quite normal. Maxilli- 

 peds with quadriarticulate palp, last joint lamellarly expanded, 

 masticatory lobe well developed, epignath oblong, oval, turned 

 in front. Legs of rather uniform structure, ambulatory, usually 

 stronger in male than in female, sometimes approach to subcheli- 

 form character, dactylus in all pairs strong, unguiform, un- 

 equally bidentate at tip. Uropoda end in single flattened joint, 

 at base of this joint outside with strong ciliated seta. Male 

 usually much larger than female. 



Key to the species. 



a. Telson truncate at hind edge. mctallica. 



aa. Telson double-concave at hind edge. balthica. 



Idotea metallica Bosc. 



Plates 78 and 150, Figure 2. 



Idotea mctallica Bosc, Hist. Nat. Crust., II, 1802, p. 179, PI. 15, fig. 6. High 

 seas. 



Stebbing, Hist. Recent Crust. (Intern. Sci. Series LXXIV), 1893, P- 



373- Great range over the world. 



H. Richardson, Amer. Nat., XXXIV, 1900, p. 226. Atlantic coast 



south to Cape Cod and North Carolina regions. 



H. Richardson, Proc. U. S. Nat. Mus., XXIII, 1901, p. 54i- Nova 



Scotia to North Carolina. 



Idothca metallica H. Richardson, Bull. U. S. Nat. Mus., No. 54, 1905, p. 362, 

 figs. 392-393. Nova Scotia to Florida, off Maryland, Chesapeake Bay. 



M. J. Rathbun, Occas. Papers Boston Soc. N. Hist., VII, 1905, P- 4i- 



(Maine, Massachusetts, Rhode Island.) 



Idotea robiista Verrill, Rep. U. S. F. Com., I, 1871-72 (1873), p. 439, PI- 5, 

 fig. 24 (note). Vineyard Sound. 



