44 Benedict Arcturidse in the U. S. National Musenm. 



Arcturus feildeni Miers. 



Arcturus baffini var. feildeni Miers, Ann. and Mag. Nat. Hist. (4), XX, 64, 

 1877. 



The head is a little broader than long when the length is measured on 



the side ; the surface presents three areolations, two circular ones a little 



in front of the line of the eyes and a long transverse one behind the eyes. 



The antennae are equal to the body in length 36 mm. ; the fourth and 



fifth joints are each 11 mm. 



The four anterior segments of the thorax are 

 without spines or tubercles ; two slight areo 

 lations near the anterior border of the second 

 and third segments do not correspond to the 

 spines of baffini, as they exist on that species 

 in addition to the spines. The fourth segment 

 is equal in length to the two preceding. The 

 three posterior segments of the thorax and the 

 two anterior segments of the abdomen are each 

 provided with a pair of small blunt spines. 



The middle surface of the abdomen is with 

 out any indication of the prominent spiny pro 

 jections oibaffini; the median line, on the other 

 hand, shows when dried a slight irregular me 

 dian groove. The conical lateral projections of 

 baffini are altogether wanting in this species. 

 The epimera are also much modified in feildeni ; 

 they are much less pointed, and are directed 

 downwards, making them inconspicuous from 

 a dorsal view. The surface of the body is gla 

 brous. The above description is based on a 

 single specimen labeled ' Camp Clay, Cape 

 Sabine; Lieut, [now General] A. W. Greely.' 

 (No. 12416, U. S. N. M.) A much larger and less 

 typical specimen is labeled l Arcturus baffini var. 

 tuberosus, Davis Straits.' This is identical with 

 the Cape Sabine specimen, except that the spines of the posterior seg 

 ments are reduced to very low tubercles. The range of variation, as in 

 dicated by the two specimens, is easily within specific limits; both are 

 far removed from A. baffini. Length of specimen from the front to the 

 abdomen 50 mm. (No. 20333, U. S. N. M.). 



Arcturus longispinis sp. nov. 



This species, though well marked, partakes strongly of the characters 

 of baffini, the type of the genus. 



The head is deeply concave in front ; the margin does not form a true 

 curve, but shows slight projections between the median and outer an 

 tennae. The eyes are triangular and conspicuously protruding. The 



FIG. 3. Arcturus feildeni. 

 (X 1K-) 



