ME. E. J. MIEES ON THE IDOTEIDiE. 17 



which is certainly theu* most marked distinctive character, i. e. 

 the considerable dilatation of the peduncular joints of the an- 

 tennae, nor does his figure represent these joints as much dilated 

 as in the specimens before me ; moreover, the characters of the 

 antennulary joints and of the anterior thoi\acic legs do not 

 eutii-ely correspond ; but these points are probably of minor 

 importance. His species corresponds with ours in its more 

 elongated form, shorter antennal flagellum, and, as the figure 

 shows, in the less prominent antero-lateral lobe of the head. 

 Should, however, the specimens in the Museum collection prove 

 to be distinct, they may probably be designated by Sars's specific 

 name megalura. Heller, it may be added, in his remarks upon this 

 species, in his account of the Crustacea collected by the Austrian 

 Expedition to the North Pole, adheres to Kroyer's diagnosis. 



GrLTPTONOTTJS CiECUS. 



Idotea caeca. Say, Journ. Ac. Nat. Sci. Phil. i. p. 424 (1818) ; Hitch- 

 cock, Rep. Geol. Mass. p. 29 (1833); Gould, Invert, of Massachu- 

 setts, p. 337 (1841); M.-Edw. Hist. Nat. Crust, iii. p. 131 (1840) ; 

 DeKay, Zool. New York Fauna, vi., Cr. p. 42 (1844) ; White, List 

 Cr. Brit. Mus. p. 94 (1847) ; Verrill, Hep. U.S. Commiss. of Fish 4- 

 Fisheries, i. p. 340 (1874); Harger, Rep. U.S. Commiss. of Fish S)- 

 Fisheries, i. p. 669, pi. v. fig. 22 (1874). 



Chiiidotea cseca, Harger, Am. Journ. Sci. Sf Arts, (ser. 3) xv. p. 374 

 (1878); id. Pr. U.S. Nat. Mus. ii. p. 159 (1879); id. Rep. U.S. 

 Commiss. of Fish Sf Fisheries, vi. p. 338, pi. iv. figs. 16-19 (1880). 



The body is very broadly ovate, narrowing rapidly posteriorly. 

 Head but slightly excavated in front for the bases of the antennae, 

 and with a more or less open notch at the sides extending nearly 

 to the eyes ; the breadth of the thorax is greater than its length, 

 and the length of the segments is greater on the sides than in the 

 median line ; the postabdomen is convex above, with the first 

 three segments very short, the fourth indicated only by lateral 

 sutures, and united in the dorsal region with the terminal seg- 

 ment, which is ovate-lanceolate, scarcely sinuated on the sides, 

 and acute at the distal end; the eyes are light-coloured and in- 

 conspicuous. Antennules longer than the peduncle of the an- 

 tennae. Antennae with the peduncular joints of moderate length, 

 not much dilated ; flagellum about 7-jointed. Epimera with the 

 postero-lateral angles acute, but not greatly prolonged backward. 

 The three anterior pairs of legs have the propus or penultimate 

 joint dilated, the dilatation being greatest in the first pair, and the 



LI»N. JOUEN. — ZOOLOGY, VOL. XYI. 2 



