THE CRUSTACEA OF NEW JERSEY. 371 



two lo rtve) in both sexes, unequally biramous, one ramus in case 

 of fourth appendage being minute rudiment and placed as usual 

 on left side. Sometimes in male somite of appendage two absent. 

 'J'elson and uropods usually better developed on left side than on 

 right. Gills phyllobranchijc (occasionally having gill-plates at 

 tip) and eleven on either side, arranged as in Parapagurns and 

 Syui pa gurus. 



This is the largest genus of the family, and embraces about 

 one hundred and fifty species, of which about a third are sub- 

 littoral, though none are found in the sea below depths of eight 

 hundred and fifty fathoms. The genus seems to reach its greatest 

 diversity in cold or sub-arctic regions of the northern hemisphere. 



Key to the Species. 



a. Shore forms, ranging only down to fourteen fathoms depth ; body more 

 or less tuberculated, not very hairy; chelipeds more or less tuberculate. 

 b. Size larger ; carpus, propodus, dactyl and pollex broad, coarsely tu- 

 berculate. pollicaris 

 bb. Size smaller : carpus, propodus, dactyl and pollex slender, granulated. 



longicarpus 

 aa. Deep-water species, rare at low-water mark, and ranging down to one- 

 hundred and fifty fathoms depth ; body more or less tuberculate to hairy ; 

 chelipeds more or less hairy to spinescent. pubescens 



Pagurus pollicaris Say. 



Plate hi. 



Big Hermit Crab. 



P<igurus pollicaris Say, Journ. Acad. Nat. Sci. Phila., I, pt. i, 1817, p. 162. 



Coast of the United States. 

 • De Kay, N. Y. Fauna, Crust., VI, 1844, p. 19, PI. 8, fig. 21. New York. 



White, Cat. Crust. Brit. Mus., XXV, 1847, P- 59- United States (Say's 



material). 



Leid,v, Journ. Acad. Nat. Sci. Phila., (2) III, 1855, p. 14Q. Great Egg 



Harbor, New Jersey. 



M. J. Rathbun, Occas. Papers Boston Soc. N. Hist.. VII, 1905, p. 14. 



Cape Cod Bay to Long Island Sound. 



Eupagnrus pollicaris Verrill, Rep. U. S. F. Com., I, 1871-72 (1873), p. 313 

 (in Lunatia and Fulgnr). 



S. I. Smith, Rep. U. S. F. Com., I, 1871-72 (1873), p. 548. Massa- 

 chusetts to Florida. 



