276 



BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



twelve articles, extend to the middle of the second thoracic segment. Termi- 

 nal segment of abdomen acutely pointed. Outer branch of uropoda much 

 longer than inner branch. Eyes placed on the posterior half of the head. 

 Sixth and seventh pairs of legs have the propodus and dactylus very much 

 more elongated than in preceding pairs of legs. . . Tecticeps alascensis Richardson 

 b. First pair of antennae, with a flagellum of sixteen articles, extend to the posterior 

 angle of the third thoracic segment. Second pair of antenna, with a flagel- 

 lum of thirteen articles, extend to the middle of the fourth thoracic segment. 

 Terminal segment of abdomen posteriorly rounded. Outer branch of uropods 

 equal in length to inner branch. Eyes placed in the middle transverse line 

 of the head. Sixth and seventh pairs of legs with propodus and dactylus 

 only gradually a little longer than those of preceding pairs of legs. 



Tecticeps convexus Richardson 



TECTICEPS ALASCENSIS Richardson. 



Tecticeps alascensis RICHARDSON, Proc. Biol. Soc. Washington, XI, 1897, pp. 181- 

 183; Proc. U. S. Nat. Mus., XXI, 1899, p. 837; Ann. Mag. Nat. Hist. (7), 

 IV, 1899, p. 181; American Naturalist, XXXIV, 1900, p. 223. 



Localities. Alaska; Kamchatka; Off Iturup Island, Kurile Islands, 

 Okhotsk Sea; latitude 60 16' north, longitude 167 41' west; Ber- 

 ing Sea, west of Pribilof Islands (106 fathoms); between Pinnacle 

 and Ulakhla, Unalaska; Bering Sea, off Nunivak Island. 

 Depth. 9-106 fathoms. 



Found in fine gray sand, pebbles, gravel, shells, black and red sand, 

 green mud, and fine dark volcanic sand. 



Outline of body oval. Surface quite smooth, but 

 covered with little points of depression. 



Head large; twice as long as any one of the 

 thoracic segments. The anterior margin is pro- 

 duced in a way to conceal the antennae, as are also 

 the ante ro- lateral margins, making the anterior 

 portion of the head in front of the e} r es much 

 broader than the posterior portion, and forming 

 very acute antero-lateral angles. This frontal 

 margin forms a very broad 

 obtuse angle with its apex in 

 the median line. On either 

 side of this apex to the antero- 

 lateral angle this portion of the head is somewhat 

 depressed. The antennae are not conspicuous, 

 lying concealed beneath the frontal margin of 

 the head. The first pair extend to the posterior 

 angle of the first thoracic segment; the flagellum consists of ten 

 articles. The second pair reach the middle of the second segment; 

 the flagellum is twelve-jointed. The eyes are dorsally situated on the 

 posterior half of the head. 



The thoracic segments are about equal in length. The first one 

 extends laterally around the posterior portion of the head, forming a 



FIG. 286. TECTICEPS AI.- 



ASCENSIS. X 2}. 



FIG. 287. TECTICEPS ALAS- 

 CENSIS. a, ANTENNA OF 

 FIRST PAIK. 6, ANTENNA 

 OF SECOND PAIR. X 5|. 



