232 
CRUSTACEA. 
ZuzARA, Leach. 
Leaflets of the fins very large ; the superior, which is the shortest, 
separates from the other to form a border totlie last segment* * * § . 
Sph/eroma, Led. 
Leaflets of a moderate size, equal, and laid one over the other |. 
In those, the impressed lines or transverse sutures of the anterior 
segment of the tail extend to its lateral edges and cut it. The first 
joint of the superior antennae forms an elongated square, or linear 
palette. 
The leaflets of the fins are uaually narrower and thicker than in 
the preceding ; the external sometimes (Cymodocea) incloses the 
other, which is prismatic ; the point at which they unite resembles a 
knot or joint. 
Sometimes the sixth segment of the body is visibly longer through- 
out all its width than the preceding ones and that which follows. 
Only one of the two leaflets projects. 
NiESA, — C ampecopea. Leach. J 
Sometimes the sixth segment of the body is as long as the preced- 
ing ones and as that which follows. 
CiLiCiEA, Leach. 
Only one of the fin-leaflets salient, the other being placed, against 
the posterior edge of the last segment 
Cymodocea, Leach. 
Both leaflets salient and directed backwards ; the sixth segment is 
not prolonged posteriorly, and the extremity of the last one presents 
a small lamina in an cmargination ||. 
Dynamene, Leach, 
Similar to the CymodocEe in the projection and direction of the 
leaflets of the fins, but the sixth segment is prolonged posteriorly, 
and the last one exhibits a mere fissure without the lamina^. 
The others, such as the 
Anthura, Leach, 
Have a vermiform body, and the antennae, composed of four joints, 
scarcely as long as the head. The leaflets of the posterior fins by 
their disposition and approximation form a sort of capsule. 
The anterior feet arc terminated by a monodactylc forceps **. 
* Dcsmai-., ConsiiL, p. 298. 
-f* Desmar., Consid., p. 299 — 302. Spherome dentcc, XLVII, .3 — Onisev.s scr- 
ratus. Fab. 
t Desmar., Cousid., Nesce hidcnic, XLVII, 2; — Campecepte it/i.t, Id., It., 1. 
§ Desmar., Consid., Cilicee de Lcdreille, XLVII I, 3. 
II Desmar., Consid., XLVIll, 4, 
Desmar., Consid., p. 297. 
** Desmar., Consid., Anihure grele, XLVl, 13; Oniscus gracilis, Mcntag., Tvp.ns. 
Lin. Soc. IX, V, 6; — Gamma7'us heieroclitus, Wyian., Phospb. Mar., II, 11, 12. 
