1881.] Hordwell Cliffs, Hampshire. 153 



aud in fact we find it so closely allied to L. gibbosida, Lam., that 

 we scarcely can separate them ; the French shell may be a little 

 flatter.] 



L. gibbosida, Lam., is also recognised by Edwards as existing in 

 the Long Mead End bed ; it is a rather less wide example than 

 the preceding. We cite both varieties under Lamarck's name for 

 the present. 



[L. pratensis, Ed. MS., is founded on a single imperfect 

 specimen from Long Mead End in the Edwards collection ; it may 

 possibly be a fragment of the preceding. It is better not to cite 

 so uncertain a species.] 



Strigilla Colvellensis, Edw. MS. This species we found abun- 

 dant in the Long Mead End bed ; in the Edwards collection are 

 also 32 from this bed and 4 from M. Headon localities. In form 

 it is much like S. Rigaultiana, Desh., of the Barton beds, but differs 

 in the angle at which the divaricating ornaments diverge ; in the 

 latter it is about 90°, but in S. Colvellensis the lines form an angle 

 considerably over 100°; this is the readiest way of distinguishing 

 the species, the hinge is much alike in both : 8. Rigaultiana is 

 slightly thicker in texture. 



The hinge has in left valve two diverging cardinal teeth 

 leaving a triangular pit between them, the right valve has one 

 cardinal and two distant lateral teeth which fit into depressions of 

 the other valve. 



Cyrena deperdita, Desh, is determined by Prof. Morris [Ap- 

 pendix to Isle of Wight Survey Memoir, p. 156] from the Long 

 Mead End bed. A shell is very abundant at Long Mead End which 

 we can scarcely separate from Deshayes' species brought from near 

 Mortefontaine ; we identify it therefore provisionally. It was 

 however determined by Edwards as C. gibbosula, Morr., though 

 under the same term were included other forms from the M. Headon 

 bed of Hordwell. The C. deperdita in Edwards' collection from 

 the Barton beds is a wider and flatter shell rather. 



C. gibbosida, Morr. Under this term Morris {ibidem, pi. VI., 

 fig. 13, 13a) figures perhaps two different forms; it is described 

 as from "Headon Series" — which part of the series is not indi- 

 cated. In Edwards' collection it comes from Lower Headon, 

 Beacon Bunny clay, and Long Mead End sands. 



[C. pisitm, Desh. ? In the Edwards collection under this name 

 are included shells which seem a shorter variety only of C. gibbo- 

 sula, Morr. (Edw.), they come from the Long Mead End sands and 

 Beacon Bunny bed below.] 



[C. cy clad if or mis, Desh.?, so determined by Edwards from 

 Long Mead End and Beacon Bunny beds, seems a flatter form of 

 his C. gibbosida. We do not consider it identical with the French 

 type, and as we have even doubts as to its separate specific 



