648 CLASS X. 
Urozeuctus (Ourozeuktes Epw.). Tail undivided, with segments 
coalesced. 
Cymothoa nob. Tail composed of six segments, distinct, moveable. 
Sub-genera: Cymothoa Lracu, Livoneca Luacu, Anilocra Lracn, Epw. 
(Anilocra and Canolira Leacu), Nerocila Leacu, Epw. Comp. W. E. 
Leracg, 1. 1. 
These animals live parasitically on different fishes. The young animals 
have a larger head, the eyes more conspicuous, a pair of feet less on the trunk, 
and a long abdomen. See Mrtne Epwarps Ann. des Sc. nat., sec. Série, 
Tom. 111, Zool. Pl. 14, fig. 3. 
Sp. Cymothoa estrum Luacn (Oniscus wstrum L. in part), Desmar. Crust. 
Pl. 47, figs. 6, 7, Cuv. R. Ani. éd. ill., Crust. Pl. 65, fig. 1; in the Baltic ; 
—Cymothoa Banksii Lyacu, Munn Epwarps Ann. des Se. nat. 1. 1. figs. 
I, 2 (copied in Guérin Jconogr., Crust. Pl. 29, fig. 2, under the name of 
Cymoth. trigonocephala), from the Cape of Good Hope, &e. 
Alitropus Epw. Antenne not covered at the base, setaceous. 
All the feet of trunk slender, terminated by a hook. Eyes two, 
marginal. 
Sp. Alitropus typus Minne Epwarps, Hist. nat. des Crust. Pl. 33, fig. 1; 
from the bay of Bengal. 
4iga Leacn. Antenne not covered at the base, anterior with 
basal joints broad, plane and apex setaceous, multiarticulate. 
Sub-genera: Pterelas GuéRtn, Rocinela Leacu ; with eyes large, 
contiguous, or confluent anteriorly. 
Comp. Gu&éRIN Magasin de Zool. 1836, Crust. Pl. 20. 
Sp. diga emarginata Lracu, Desmar., Crust. Pl. 47, figs. 4, 5;—#ga 
bicarinata LEacu, RAatHKE Beitr. zur Fauna Norwegens, Tab. Vi. figs. \1— 
18, pp. 25—35- 
Cirolana LEACH. 
Eurydice Leacu, Epw. (Hurydice and species of Nelocira Leacn). 
Serolis Leacn. Antenne four, long, not covered at the base, 
with basal joints thicker, setaceous at the apex. Eyes two, large, 
reniform, situated in a tubercle, remote from the margin of head. 
Trunk broad, marked by a longitudinal furrow on each side. 
Abdomen with only three or four segments distinct, the last very 
large. Feet of the first pair (or in males, of first and second) thick, 
short, with strong incurved hook. 
