ISOPODS OF NORTH AMERICA. 



337 



I 



the posterior })()rti()n, two on cither side of the niediiiii liii(\ and three 

 hiteral ,spiIl(^s; the third thoracic segment has two spines on tiie 

 anterior portion, one on either side of the median line, four spines 

 on the posterior portion, two on either side of the median line, and 

 four hit(n"al spines; the fourth segment has two spines on the anterior 

 part, one on either side of the median line, four spines on the poste- 

 rior ])art, two on either side of 

 th(> median line, and four lateral 

 spines; the tifth segment has two 

 spines widely separated, one on 

 either side of the median line, 

 and one lateral spine; the sixth 

 and seventh segments have six 

 spines, three on either side of the 

 median line, and one lateral 

 s[)iiie. 



The tirst two abdominal seg- 

 ments have each eight small 

 spijies, four on either side of the 

 median line. The terminal s(>g- 

 ment has one median row of 

 spines and a row on either side 

 of this and a lateral row. The 

 median row consists of live small 

 spines and one large terminal 

 spine. The dorsal row on either 

 side of the median row each con- 

 sists of four spines. The outer 

 marginal lateral rows each con- 

 sists of three spines, a pair at 

 the base, a pair about the middle, and a pair at the extremity. At the 

 l)ase of the segment is a transverse row of four small spines. The 

 opercular valves have each a longitudinal row of eight spines. 



Both the anterior and the posterior pairs of legs are covered with 

 spines, the anterior ones more densely. 



Two specimens, one imperfect, were obtained by the U. S. Bureau 

 of Fisheries steamei- AJhafrost< at Fernandina, Florida. 



Ty2)e.—Q'dt. No. 11522, U.S.N.M. 



ARCTURUS BAFFINI (Sabine). 



hlotea haffini Sabixr, Suppl. to App. to Capt. Parry's Voyage, 1824, p. 228, pi. i, 



figH. 4-6. 

 Arcturns iuberculatus Latreille in Cuvier, Regne Animal, 2d ed., IV, 1829, p. 189. 

 Arcturus haffini Westwood, Trans. Entom. Soc, London, I, 1836, p. 72. — Milne 



Edwards, Hist. Nat. Crust, III, 1840, p. 123, pi. xxxi, fig. 1.— G. 0. Sars, 

 28589—05 22 



Fig. 36t'). — ARCTUurs kluuidanus. 



