S4< ME. E. J. MIEES ON THE IDOTEIDJ. 



In Brandt's figure and in the British- Columbian examples the 

 postabdomen about equals the last four thoracic segments in 

 length. In the Japanese example the postabdomen about equals 

 3-|- segments. 



In the collection of the Paris Museum is a male (Mus. St. Peters- 

 burg) that agrees very nearly with the above description, but the 

 keel on the terminal segment is partially obsolete, antennae 14- 

 15-jointed ; in tvpo males from the Amur (M. A. Edwards) the 

 keel is obsolete and the flagellum (only one perfect) 11-joiuted. 

 A fine male without locality (Exped. de la Venus, M. Neboux) 

 has no trace of a dorsal keel, and has a 12-jointed antennal fla- 

 gellum. 



The Idotea rectilinea of Lockington (Proc. Cal. Acad. Sci. vii. 

 l)t. i. p. 36, 1877) is described as having the body slender, all 

 the thoracic segments equal in length and width. Postabdomen 

 rectilinear, nearly as wide as the thorax, with the first two seg- 

 ments distinct ; its total length about equal to that of the last 

 three thoracic segments ; its posterior extremity obtusely pointed. 

 Antennae long ; ])eduucle equal in length to the three first seg- 

 ments of the body ; flagellum broken in both specimens. Colour 

 variable : one dried specimen almost entirely black, the other with 

 a black line down centre of body, the rest of whicli is yellowish. 

 Length 0-80 inch, width 0-17 inch. 



Log. San Diego. 



Nothing is stated concerning the epimera ; but, as far as the 

 description goes, this species is scarcely to be distinguished from 

 the foregoing. 



Idotea ueotoma. 



Idotea urotoma, Stimpson, Pr. Ac. Nat. Sci. Phil. p. 155 (1864). 



According to Stimpson, this has the body nearly linear, nearly 

 five times as long as broad, broadest at the sixth thoracic segment. 

 Postabdomen consisting of three joints, with the partial separa- 

 tion of a fourth, subrectangular, with convex extremities, and 

 scarcely less broad at its truncate posterior extremity than at the 

 anterior. The posterior extremity is peculiar in shape, the angle 

 on either side projecting strongly, and separated by a tooth from 

 the convex or subtriangular middle j)ortion, which bears a small 

 tooth at the middle. Antennae a little more than half as long as 

 the body ; last two joints of the peduncle subequal ; flagellum 

 a little shorter than the peduncle and 10-jointed. Thoracic legs 



