232 CRUSTACEA. 



ZuzARA, Leach. 



Leaflets of the fins very large ; the superior, which is the shortest, 

 separates from the other to form a border to the last segment*. 



Sph^roma, Lat. 



Leaflets of a moderate size, equal, and laid one over the other f . 



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 Avidth than the preceding ones and that which follows. 



Only one of the two leaflets projects. 



N;esa, — Campecopea. Leach. % 



Sometimes the sixth segment of the body is as long as the preced- 

 ing ones and as that which follows. 



CiliCvEA, 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 emargination ||. 



Dynamene, Leach, 



Similar to the Cymodocre 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 are terminated by a monodactylc forceps **. 



* Desmar., Consid., p. 298. 



t Desmar., Consid., p. 299—302. Sphdoinc dentcc, XLVII, 3—Oniscvs scr- 

 ralus, Fab. 



X Desmar., Coasid., Nesee bidenie, XLVII, 2; — Catiq:ecci:cv vchie, Id., It., 1. 



§ Desmar., Consid., Cilicee de Laireille, XLVIII, 3. 



II Desmar., Consid., XLVIII, 4, 



^f Desmar., Consid., p. 297. 



** Desmar., Consid., Anthure grele, XLYI, 13; Oniscus gracilis, Mowing., Ix^ws,. 

 Lin. Soc. IX, V, 6; — Gammani.sheteroclitus,\Wis.n., Phosph. Mar., II, 11, 12. 



