some British Fossil Crustacea. 169 
small and smooth, second, third and fourth each with a pair 
of tubercles on the elevated middle portion, fifth smooth, with 
a smail triangular piece (remains of the embryonic tail-fin) 
on each side between it and the sixth or last joint, which is 
subpentagonal and rather more than twice the length of the 
fifth ; tail of the female broad ovate, smooth, trilobed ; ante- 
rior pair of feet forming short robust chele, with scattered spl- 
nose tubercles ; the others small and smooth, the two hinder 
pair abruptly smaller and elevated above the rest. Length of 
carapace 10 lines, width 9 lines. 
Common in the London clay of Sheppey. 
(Col. University of Cambridge and Mr. Bowerbank.) 
Notopocorystes (M‘Coy), n. g. 
Ktym. voétos, dorsum, trovs, pes, and Corystes. 
Gen. Char. Carapace longer than broad, ovate, depressed, with 
scattered tubercles, anterior half broadly rounded and fur- 
nished with a few strong marginal teeth ; 
posterior lateral margins acute, straight, 
rapidly converging towards the base, 
which is narrow and deeply emarginate ; 
front forming a short triangular rostrum, 
depressed in the middle, and with a small 
mesial ridge; orbits large, transversely 
oval, complete below and above, with two 
longitudinal fissures in the upper margin; 
gastric region very large, rhomboidal, de- 
fined posteriorly by a strong obtusely an- 
gular nuchal furrow pointing backwards, 
shghtly convex, extending nearly the width 
of the carapace, leaving a very small ob- Back view and profile 
scurcly defined hepatic region on each side; of Notopocorystes. 
genital region very small, about twice as wide as long, not 
dividing the gastric region ; cardiac region moderately large, 
hexagonal, with a small deep lunate fossa on each side at its 
junction with the genital region ; intestinal region narrow ; 
branchial regions large, each divided by a shallow furrow pro- 
ceeding from the base of the genital region to the lateral mar- 
gin on each side, parallel with the nuchal furrow; plerygostomian 
regions very tumid; first paw of feet short, robust, didactyle 
spinulose ; fifth pair of feet disproportionally small and elevated 
above the level of the others ; abdomen of the male narrow 
(? six-jomted). 
This little genus completes the chain of affinities between the 
recent genera Homola and Corystes, rendering the transition per- 
