24 ME. J. CA.EIER ON THE PALJEONTOLOGT OF [Eeb. 1 898, 



Banma, as defined by Lamarck, has been divided by Brocchi 

 into the subgenera JRanina proper, Raninella, and Palceonotopus. 



EaNIN^A (EAKEfELLA ?) ATAVA, Sp. nOV. (PI. I, fig. 7.) 



Description, — Carapace about a fourth longer than wide, mode- 

 rately convex transversely ; in outline elongate- ovoid. Width of 

 orbito-frontal border equal to half that of the carapace. Buccal 

 orifice large, two-fifths of the carapace in length. External 

 maxillipeds correspondingly elongated, supported upon large basal 

 segments. Anterior portion of sternum widely trifid, largely 

 excavated laterally for the insertion of the chelae ; posterior portion 

 rapidly reduced in width so as to become linear. Length of 

 carapace = nearly 50 mm. ; width =38 mm. 



Distribution. — The only specimens known to me are : — One in 

 the Brighton Museum (G, 2329 AVillett Coll.), from the Upper 

 Greensand of Chute Parm, Wiltshire ; and another in the British 

 Museum (No. 59527, Cunnington Coll.), also from the Upper 

 Greensand of Wiltshire. 



Pamily Oxystomata. 

 Genus Pal^ocoetstes, Bell. 



Pal^ocoeystes NoemajSti, Bell. 



1863. Bell, Monogr. pt. ii, p. 16 & pi. iii, figs. 10-12. 



This form appears to have very slender claim to specific dis- 

 tinction ; it occurs only in the Chalk, and can scarcely be regarded as 

 other than a robust, vigorously- grown, variety of P. Sto'kesi. Nearly 

 all the Crustacea which are common to the Chalk and Upper Green- 

 sand attain fuller development in the former than in the latter 

 rock. The type is in the Woodwardian Museum (Leckenby Coll.) ; 

 four other specimens from the Grey Chalk of Dover are in the 

 British Museum. 



Pal^ocoexstes Stokesii (Mantell). (PL I, fig. 8.) 

 1863. Bell, Monogr. pt. ii, p. 15 & pi. iii, figs. 1-9. 



Suj)j)lert2entary. — The small lateral teeth upon the rostrum, to 

 which Bell refers, are seldom observable. The gastric lobes are 

 indistinctly defined. The base of the mesogastric lobe in Gault 

 examples bears a single areolar tubercle, but the Greensand form 

 bears three or four. The posterior border is slightly narrower than 

 the orbito-frontal. The orbits have a single fissure in the lower 

 border and two in the upper. The sides of the buccal opening are 

 curved. The episternum is unusually small, and pentagonal in 

 shape. A solitary specimen, in the Woodwardian Museum, of a 

 detached propodite which may almost certainly be referred to this 

 species suggests the probability that in the fossil form — as in its 

 living representative Corystes Cassivelanus — the first pair of limbs 

 was much longer in the male than in the female. I have not, 

 however, met with a male carapace having the chelae intact. 



