occurriwj on the Noriceyian Cueists. 335 



the first two pairs of legs. As I do not know Milne-Edwards's 

 genus, from which this, perhaps, differs but little, I have re- 

 ferred to Costa's genus a new species which is not uncommon 

 on the shores of Bergen and Throndhiem. It also agrees in 

 many respects with ^rton^/a-, from which it cannot be separated 

 by the elongated antennae, as A. littoralis likewise possesses 

 these — or because the first pair of feet have no prehensile hand, 

 as this is also wanting in A. Vahlii. The })eculiar form of the 

 respiratory lamella, however, is what especially distinguishes 

 it ; and this is also described by Costa. These are very large 

 and triangular, and furnished in the middle with a longitudinal 

 fold, like the midrib in a leaf, from which closely approximated 

 transverse folds are given off, like the secondary ribs. These 

 folds are very deep, and give the respiratory plates quite a 

 peculiar form. This, however, is not exclusively characteristic 

 of this genus, as I have found the same structiu-e in Amjyhitoe 

 (Ejndesma) coiivpressa^ Lilljeb., but only in the last respiratory- 

 plate. The second pair of abdominal feet are also of an un- 

 usual form : their branches are dissimilar in structiu-e ; the 

 inner one, which is the shortest, is very broad in its first half, 

 and then suddenly contracted, so that only the inner border is 

 continued into a cui'ved, acute, and long spine, and from the 

 truncated outer side issues a long thick seta. In other respects 

 the genus resembles Anonyx. 



I. spinicorni'sj mi hi. — This species attains a length of 30-40 

 millims. The peduncle of the superior antennae is short ; its 

 first joint, which is much longer than the following two to- 

 gether, is produced below into a strong spine ; a similar one 

 occurs on the inner side of this, as also on the second joint. 

 The third joint of the ilagellum is short ; the other (still shorter) 

 joints amount in the females to 66, in the males to about 100, and 

 in the latter they are furnished with sucking-disks alternately 

 on the two sides. The inferior antenna3 are longer than the 

 the superior ; the fifth joint is shorter than the fourth, and the 

 flagellum consists of 80-120 joints. The feet of the first pair 

 differ from those of A. Costa's /. Tanros in the second joint in 

 our species being very long and the fourth scarcely longer than 

 the fifth. The third joint of the second pair of feet is in om* 

 species much longer than the fourtli, and the fourth consider- 

 ably shorter than in the species described by A. Costa. The 

 three hinder thoracic legs successively increase considerably in 

 length. The telson is very long, and cleft to beyond the middle. 

 The inferior posterior angle of tlic third abdominal segment 

 forms a small upturned hook. 



Urothoe, Dana. — Dana established this genus, with which 

 A. Costa's Egidea perhaps coincides, upon two species from 



