16 FOSSIL MALACOSTRACOUS CRUSTACEA. 



male ; the segments are all separate ; an obtuse carina extends as far as the middle of the 

 seventh segment, and each of the segments from the second to the fifth has a small 

 tubercle in the centre, and a still smaller one on each side ; the sixth segment is nearly 

 square, and the seventh semioval. 



Length of carapace, 1'4 inch ; breadth, 1*2 inch. 



Common in the Gault at Folkestone, Maidstone, &c, and still more so in the upper 

 Greensand at Cambridge. 



Obs. This species was first noticed by Mantell, who obtained it at Ringmer, in 

 Sussex, and announced it first in the ' Geology of Sussex/ and afterwards in the ' Geology 

 of the South-East Coast of England.' He subsequently described it, under the name of 

 Corystes Stokesii, in the ' Medals of Creation,' in the year 1844. Professor M'Coy, in 

 1849, made it the type of his genus Notopocorystes, and gave a tolerably full description 

 of it, as N. Mcmtetti, expressing at the same time his suspicion that it may be identical 

 with Mantell's species. 



It occurs very commonly in the Gault at Folkestone, and in innumerable quantities in 

 the upper Greensand at Cambridge. There are numerous specimens from both these 

 localities in every collection which contains fossils from these prolific beds. 



Pal^eocorystes Normani, mild. Plate III, figs. 10 — 12. 



Testa ovata, valde convexa, regione cardiaca tuberculis tribus in serie longitudinali ; 

 regione gastrica in media lsevi, ad latera utrinque tuberculis quatuor minoribus. 



Descr. Carapace ovate, one fifth longer than it is broad, very convex, the height 

 from the plane of the lowest part of the lateral margin to the highest point of the carapace 

 being two fifths of the transverse diameter ; the margins almost evenly rounded ; the 

 orbits and frontal region somewhat advanced, narrow, and truncate ; latero-anterior margin 

 with three small teeth, latero- posterior margin granulated ; the surface of the carapace 

 glabrous, excepting the posterior portion, which is slightly granulated ; tubercles few, 

 three or four small ones on the lateral portion of the gastric region, and three on the 

 median line on the cardiac ; orbits approximate, with two conspicuous fissures in the upper 

 margin, and a small tooth at the outer angle. 



Length of carapace, 1*4 inch; breadth, 1 inch; height, from the plane of the lateral 

 margin, 4 inch. 



A single specimen only has come under my observation ; it is from the Chalk Marl of 

 Ventnor, in the Isle of Wight, and in Mr. Norman's collection, to whom I gladly take 

 the opportunity of recording my obligations, for kindly placing his specimens at my disposal, 

 by dedicating this species to him. 



