26 ME. J. CAKTEE ON THE PALAEONTOLOGY OF [Feb. 1 898, 



curved. External maxillipeds slender ; exopodite and endopodite 

 nearly equal in width ; meros of the endopodite elongated, two- 

 thirds as long as the ischios. Chelae of moderate size ; meros sub- 

 terete, granulate, dentate on both borders ; carpus cuboid ; hand 

 compressed, rather longer than wide, both borders somewhat tren- . 

 chant and serrated by several teeth. The chelae correspond closely 

 with those of E. Broderipii. Abdomen seven-jointed ; penultimate 

 segmeiit twice as long as the fifth. Telson rounded at its extremity, 

 rather longer than wide. Length of carapace =15 to 35 mm.; 

 length of average adult =25 mm. 



Memcu'Jcs. — I have examined upwards of 200 specimens of this 

 species, all of which were obtained from the Cambridge Greensand. 

 I am not aware that it has been found elsewhere. 



M'Coy regarded the peculiar series of strap-shaped markings on 

 the surface of the carapace as representing the normal dorsal 

 lobes ; but Bell does not assent to this opinion. I would suggest it as 

 probable that they are modifications produced by the confluence 

 or expansion of prominences which occur in the form of areolar 

 tubercles in Necrocarciniis, Campylostoma^ and other genera. This 

 interpretation of their morphological significance is suggested by a 

 specimen in my own collection figured by Bell (pi. xi, fig. 16) 

 which has three elevated lobes on the scapular region, similar to 

 those on the cephalic area : in this respect corresponding precisely 

 with the position normally occupied by areolar tubercles in other 

 genera. 



Distribution. — Cambridge Greensand. Specimens are in the 

 British Museum, the Museum of Practical Geology, the Wood- 

 wardian, York, Glasgow, Northampton, Nottingham, and other 

 Museums. 



Genus Ctclocoetstes, Bell. 

 Ctclocoetstes pulchelltjs, Bell. 



1858. Bell, Monogr. pt. i, p. 24 & pi. iv, figs. 1 & 2. 



1863-64. Necrozius Boiverbankii, Milne-Edwards, Ann. Sci. Nat. ser. 4, vol. xx 

 (1863) pi. xii, fig. 2 ; ser. 5, vol. i (1864) p. 58. 



1867. Necrozius BowerbanJcii, Milne-Edwards, Geol. Mag. p. 531 & pi. xxi, 

 figs. 2 & 3. 



Supplementary . — Carapace rotundo-quadrate in outline, deflexed 

 in front, rather wider than long. Orbito-frontal border equal to three- 

 fifths of the width of the carapace, nearly straight. Granules on 

 the dorsal surface uniform in size and regular in disposition ; inter- 

 spaces ver)^ minutely punctated (seen with a lens). Most of the 

 normal cephalic and scapular lobes distinct, separated by unusually 

 wide smooth sulci ; central portion of each lobe granulated, basal 

 portion smooth. Orbits rather small, with granulated edges ; two 

 distinct fissures in the upper and one in the lower border. Antero- 

 lateral border with two or three slightly-produced processes, which 

 have granulated summits and are surrounded at the base by a 

 smooth space. Posterior border delicately and regularly granulated. 

 Abdomen, in the male, seven-jointed, rapidly tapering to a small 



