330 BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



first being many times longer than the second. The second antennae 

 are 53 mm. in -length. The palp of the maxillipeds is composed of 

 five articles. 



The first segment of the thorax has two small tubercles or rudiments 

 of spines, one on either side of the median line. The spines of the 

 second, third, and fourth segments are 6 mm. in length, placed one on 

 each side of the median line. The spines of the fifth segment are 2 

 mm. long, one on either side of the median line. The spines of the 

 sixth segment are 2 mm. long, placed one on either side of the median 

 line. The spines of the seventh segment are 1 mm. long, situated one 

 on either side of the median line. Epimera are distinct on all but the 

 first segment. They increase in size from those of the second to those 

 of the fifth segment, which are the largest, and then decrease in size; 

 all have the lateral margins rounded. The epimera of the second, 

 third, and fourth segments are concealed in a dorsal view by the large 

 knob-like projections on the lateral margins of the segments. 



The abdomen is composed of three segments, the first two of which 

 are short and are armed each with two spines, one on either side of 

 the median line, those of the first segment being rudiments as in the 

 first segment of the thorax, while those of the second segment are 2 

 mm. long and project backward. The first segment has a triangular 

 expansion on either side of the lateral margin. The second has none. 

 The terminal segment has two backward projecting spines situated on 

 the dorsal surface, one on either side of the median line about the 

 middle of the segment. This segment is very much compressed 

 laterally. It terminates in two short points. The lateral margin has 

 a triangular expansion on either side at the base and a smaller one on 

 either side just below the middle of the segment. 



The first four pairs of legs are directed forward and are strongly 

 ciliated. The last three pairs are ambulatory. 



ARCTURUS GLABER Benedict. 



Arcturus glabrus BENEDICT, Proc. Biol. Soc. Wash., XII, 1898, p. 46. 



Arcturus glaber RICHARDSON, Proc. U. S. Nat. Mus., XXI, 1899, p. 855; Ann. 



Mag. Nat. Hist. (7), IV, 1899, p. 277; American Naturalist, XXXIV, 1900, 



p. 230. 



Locality. Bering Sea. 



Depth. 55 fathoms. 



Body narrow, elongate, a little over six times as long as broad, 5 mm. : 

 31 mm. Head wider than long, 3 mm. : 4 mm. The head measures 

 4 mm. in length from the antero- lateral angles to the posterior margin. 

 The front is deeply excavate between the produced lateral angles. 

 The eyes are small, transversely ovate, composite, and situated at the 

 sides of the head, halfway between the antero-lateral angles and the 



