1862.] DR. BAIRD ON NEW PHYLLOPODOUS CRUSTACEANS. 147 
5. DESCRIPTION OF SEVERAL NEw SPECIES OF PHYLLOPODOUS 
CRUSTACEANS, BELONGING TO THE GENERA ESTHERIA AND 
Limnetis. By W. Barrp, M.D., F.L.S. 
(Plate XV.) 
1. Ester sonest, Baird. (Pl. XV. figs. 1, 1a, 18, 1e, 1d.) 
Carapace of a comparatively hard, horny structure, and of a dark- 
brown colour. Valves ventricose, rounded, ovate. Umbones pro- 
minent, nearly central, but a little nearer anterior extremity ; invo- 
lute and representing exactly those of a bivalve shell. Dorsal margin 
short; ventral rounded. Anterior extremity swollen, rounded, 
shorter than posterior extremity, which is somewhat compressed and 
rounded. Ribs numerous and narrow. ‘Those of the upper half of 
carapace, from the umbo downwards, strongly developed, the edges 
being raised and strongly beaded; the interstices hollow, and more 
sparsely dotted with rather small irregular-sized punctations. Ribs 
of lower half of carapace, as far as the ventral margin, much smaller 
than those of upper half, narrower, and much more numerous ; they 
are punctate also; but the interstices are so very narrow that no 
sculpture can be seen. Internally the surface is quite smooth, and 
of a dark-purple colour. 
Length of carapace, 6 lines; breadth at umbo, nearly 5 lines. 
Hab. Brackish water, Island of Cuba (Dr. Dunker), Commu- 
nicated by T. R. Jones, Esq. (Mus. Brit.) 
2. EsTHERIA DUNKERI, Baird. (PI. XV. figs. 6, 6a, 66.) 
Carapace-valves broadly ovate and somewhat elongate. Umbones 
prominent, and placed at some distance (rather more than a third) 
from anterior extremity. Dorsal margin short, rather sloping. 
Ventral margin nearly straight, or only slightly rounded. Anterior 
extremity swollen, very convex, and rounded. Posterior extremity 
elongate, more compressed, and not so rounded. The carapace is of 
a uniform yellow horn-colour, thin, and translucent. Ribs numerous, 
elevated, rather narrow, about twenty-seven in number, with the in- 
terstices marked with shallow pits and extremely fine punctations. 
This species approaches somewhat to LZ. brasiliensis, but differs 
in the position of the umbones, those of H#. dunkeri being further 
from the anterior extremity. The relative size of anterior and poste- 
rior extremities differs also, the former in ZL. brasiliensis being much 
broader than in the present species. It is a larger species also than 
E. brasiliensis. 
Length of carapace, 7 lines; breadth at umbo, 4 lines. 
Hab. Zimapan, Mexico; in fresh water (Dr. Dunker). Com. 
municated by T. R. Jones, Esq. (Mus. Brit.) 
3. EstHerta torTt, Baird. (Pl. XV. figs. 2, 2a, 2.) 
Carapace of a very light amber-colour, oval, rather swollen. Um- 
bones very prominent, elongate, placed near the anterior extremity. 
Dorsal margin slightly sloping. Ventral margin rounded. Anterior 
