ZooL.— Vol. III.] HOLMES— WEST AMERICAN CRUSTACEA. 317 



Peduncles of the uropods prismatic in section with prominent angles; 

 peduncle of the first pair reaching to about | the length of the peduncle of 

 the second pair, rami acicular, somewhat flattened, shorter than the pedun- 

 cle, the inner ramus broader and slightly longer than the outer; peduncle of 

 the second pair of uropods reaching the extremity of that of the third pair; 

 peduncle and rami of the third pair of subequal length. All the uropods are 

 nearly alike in character and the tips of the rami extend to about the same 

 distance posteriorly, those of the second pair slightly exceeding those of the 

 first and third; the margins of the rami are armed with numerous minute 

 spines. Telson oblong, a little longer than the upper portions of the 2 last 

 abdominal segments, raised along the mid-dorsal line, broadly emarginate 

 at the tip, and rounded at the postero-lateral angles. 



Length 35 mm. 



Described from Mr. Lockington's four type specimens 

 which came from the " west coast of Alaska, north of Beh- 

 ring's Straits " (No. 3561, collection of the California 

 Academy of Sciences). 



This species is allied to A. Mahngreni {Go'q.s,) but differs 

 in having a more strongly curved rostrum, in having the 

 postero-lateral angles of the anterior abdominal segments 

 flattened or broadly rounded, instead of produced into 

 spines, and in having no tooth near the middle of the palm 

 of the gnathopods. The general shape of the hands in the 

 two species is also very different. It is probable that 

 Stuxberg confused this species with Malmgreni as his 

 figure, which is copied by Delia Valle to illustrate the latter 

 species, agrees closely with Miers' figure of fulchra and 

 differs markedly from the original figure of Malmgreni 

 given by Goes. 



Family EUSIRID^. 



Rhachotropis aculeata (Lepechin). 



Oniscus aculeatus Lepechin, Acta Acad. Sci. Imp. Petrop. 1780, p. 247, 



tab. viii, fig. I. 

 Rhachotropis aculeata Smith, Proc. U. S. Nat. Mus. v. 6, pp. 222, 229, 1884. 



Stabbing, Challenger Reports, v. 29, p. 954, 1888. 

 Pontogeneia aculeata Delia Valle, Fauna und Flora des Golfes von Neapel, 



20 Monogr. p. 616, tav. lix, fig. 28, 1893. 



A single specimen of this species was found in the bottle 

 containing Lockington's types of Oediceros behringiensis. 

 For further references and synonyms see Stebbing, /. c, or 

 the monograph of Delia Valle. 



