CYTHERE. 171 



b'. CYTHERE AURANTIA. Tab. XXI, fig. 8. 



CYTIIERE AURANTIA, Baird, Mag. Zool. and Bot., ii, 143, t. 5, f. 26, 



1835 ; Trans. Berw. Nat. Club, ii, 153. 

 M. Edwards, Hist. Nat. Crust., iii, 408. 



Shell somewhat reniform, rounded and rather promi- 

 nent on upper margin ; slightly sinuated underneath, the 

 posterior extremity rather broader than the anterior. The 

 valves are smooth, glaucous, and of a bright orange colour. 

 This species is very minute. 



Hob. Berwick Bay; 1835. 



7. CYTHERE NIGRESCENS. Tab. XXI, figs. 4, 4. 



CYTHERE NIGRESCENS, Baird, Mag. Zool. aiid Bot., ii. 143, t. 5, f. 27, 



1838 ; Trans. Berw. Nat. Club, ii, 153. 

 M, Edwards, Hist. Nat. Crust., iii, 409. 



Shell gibbosely ovate, anterior extremity rounded, nar- 

 rower than posterior, which is marked by a gibbous pro- 

 jection above and below, and is terminated by a sharp 

 point. The valves are quite smooth and free from hairs, 

 of a dirty, black colour, and translucent, showing the 

 body of the animal, which is of a very dark hue, shining 

 through. 



Hob. Berwick Bay; not uncommon; 1835. Dover, 

 September 1849. Arran, Boston, &c., in sand; W. C. 

 Williamson, Esq. 



8. CYTHERE MINNA. Tab. XX, figs. 4, 4 a-d. 



BAIRBIA SILIQUA (var. c. ?), T. R. Jones, Eutomost. of the Cretaceous 



Formation of England. 



Shell elongate ovate, bluntly conical on the dorsal mar- 

 gin, nearly plain beneath ; obtusely rounded on anterior 

 extremity ; sharply acute posteriorly, and narrow, the ex- 

 tremity of the shell being produced into an acute point. 

 The valves are smooth, glabrous, white, and pellucid. 

 This is totally different from any yet described, and is a 

 /ery distinct species ; it is the largest of all I have seen. 



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