CYPRINA. 133 



Cypeina Sedgwicki (Walker), I860. Plate XIX, fig. 14. Plate XX, figs. 1-5. 



18G6. Sph^ea Sedgwickii, J. F. Walker. Ann. Mag. Nat. Hist., ser. 3, vol. 



xviii, p. 386, pi. xiii, figs. 1, 2. 

 1867. Cypeina angui.ata, var., H. G. Seeley. Ibid., ser. 3, vol. xx, p. 27. 

 1875. — Sedgwickii, W. Keeping in T. G. Bonney. ' Cambridgeshire 



Geology,' p. 68. 

 1883. W. Keeping. Foss., etc., Neoe. Upware and Brick- 



hill, p. 123, pi. vi, fig. 12. 



Description. — Shell more or less oval, sometimes sub-triangular, rounded, inflated, 

 slightly or moderately inequilateral ; length as a rule not greatly exceeding the 

 height. Lunular margin of moderate length, concave. Anterior margin rounded, 

 passing gradually into the convex ventral margin. Postero-dorsal margin moderately 

 convex. Umbones prominent, broad, curved inward and forward. Carina absent 

 or indistinct. Postero-dorsal region convex, rounded. Lunule large, ovate, 

 bounded by a faint groove. Escutcheon long, bounded by a more or less distinct 

 carina. Ornamentation consists of growth-lines. 



Measurements : 





(i) 



(2) 



(3) 



(4) 



(5) 



(6) 



(7) 



(8) 



(9) 



Length 



39 



38 



37 



37 



34 



32 



31 



27 



23 mm 



Height 



34 



31 



31 



32 



31 



26-5 



27 



24 



90 



Thickness 



29 



25 



26-5 







23 



24 





55 



(1 — 9) Lower Creensand, Upware. 



Affinities. — This species is closely related to, and may perhaps be only a local 

 variety of G. Saussuri (see above). The chief points in which it differs from the 

 latter are (1) the carina is absent or indistinct, (2) the posterior margin is 

 relatively higher, (3) the valves are usually more inflated, (4) the shell is usually 

 less triangular in outline and less inequilateral. 



Remarks. — The examples of G. Sedgwicki vary in relative height and length, 

 and consequently in outline. The longer forms approach C. Sanssuri more nearly 

 than the shorter forms. 



This species was placed in the genus 8}>li3era by Mr. J. F. Walker, but was 

 subsequently referred to Gyprina by Seeley and by W. Keeping. 



Type. — From Potton, in Mr. J. F. Walker's collection. 



Distribution. — Lower Greensand of Upware and Potton. 



Cypeina obtusa, Keeping, 1883. Plate XX, fig. 6. 



1883. Cypeina obtusa. W. Keeping. Foss., etc., Neoc. Upware and Brickhill, p. 



124. pi. vi. fig. 13. 



18 



