76 ME. E. J. MIEES ON THE IDOTEID^. 



Chili, at Yina del Mar, three leagues north of Yalparaiso (on 

 the upper surface and embedded among the tentacles of an 

 Asterias). 



There is a slight pubescence and a few very short hairs at the 

 extremity of the postabdomen ; the opercular plates completely 

 cover it below, and have hirsute margins. The antennae are 

 stoutish, and bear a few short hairs. 



In the above citation I have combined in great measure Dana's 

 generic and specific descriptions and subsequent remarks. 



As in jE^. chilensis, the postabdomen is biarticulate, with the 

 sides at base subparallel, head with a median frontal lobe, the 

 first pair of legs the shortest. 



Cleantis. 



Cleantis, Dana, Amer. Journ. of Sci, and Arts, (ser. 2) viii. p. 427 (1849), 

 xiv. p. 300 (1862); id. U.S. Expl. Exped. xiv. {Cr. 2) pp. 697, 707 

 (1853). 



Erichsonia, Dana, Amer. Journ. of Sci. and Arts, (ser. 2) viii. p. 427 

 (1849), xiv. p. 300 (1852) ; id. U.S. Expl. Exped. xiv. {Cr. 2), pp. 697, 

 709 (1853) ; Harger, Rep. U.S. Fish Comm. pt. vi. Isopoda, p. 354 

 (1880). 



Body more or less slender and elongated, narrow oblong or 

 subelliptic, or very slender. Head transverse, with the eyes 

 placed near to the lateral margins. Postabdomen with all the 

 segments coalescent, or composed of two to five distinct segments. 

 Antennules small. Antennae well-developed, geniculate or non- 

 geniculate, with the joints of the flageilum all consolidated and 

 forming a single piece. Epimera distinct, small, some or all of 

 them visible in a dorsal view. Legs slender, subsimilar; the 

 penultimate joints of the three anterior pairs not dilated. Oper- 

 cidar valves nearly as in Idotea. 



§ Postaldomen with all its segments coalescent. {Evichsoma^^ 



The species of this section may apparently be distinguished as 

 follows : — 



Elliptical, broadest in the middle : head with two distinct 

 frontal tubercles ; first and second thoracic segments triangulate 

 on the sides. 1. C. angnlata (Dana). 



Suboblong : head with a bifid tubercle on its upper surface ; 

 thoracic segments laterally more or less angulated. 



2. G.filiformis (Say). 



