KEPORT ON THE LAMELLIBRANCHIATA. 295 



The right valve of this species is usually white or onl)' partly tinted with purplish-red, 

 and contrasts strongly with the red-rayed left valve. The specimen figured Ly Reeve is 

 rather abnormal in colour, as the ribs in most specimens are not alternately dark 

 and pale. 



Pecten pusio (Linn^). 



Ostrea pusio, Linn(5, Syst. Nat,., ed. 12, p. 1146. 



Pecten ptisio, Forbes and Hanley, Brit. Moll., vol. ii. p. 278, pi. 1. figs. 4, 5, pi. li. fig. 7. 



Pecten pusio, Jeffreys, Brit. Conch., vol. ii. p. 51. 



Pecten pusio, Jeffreys, Proc. Zool. Soc. Lend., 1879, p. 557 



Habitat. — Tenerife, Canary Islands, in 70 fathoms ; and Station 75, Azores, in 

 450 fathoms. 



In this, as in other instances, I refrain from giving the copious synonymy and refer- 

 ences to a great number of works, a course only excusable in preparing a monograph. 



Pecten sulcatns, Muller, A^ar. 



Pecten sulcatus, Muller, 1776, Zool. Dan. Prodrom., p. 248, No. 2995. 



Pecten sulcatus, Jeffreys, Proc. Zool. Soc. Lond., 1879, p. 557. 



Ostrea arata, Gmeliu, Syst. Nat., p. .3327, No. 60. 



Pecten aratus, Sars, Moll. Eeg. Arct. Norv., p. 17, pi. ii. tigs. Sa-S?*. 



Pecten idams, Eeeve, Conch. Icon., vol. viii. pi. xxxiii. fig. 153. f 



Habitat. — Station II., off' the coast of Portugal, in 470 fathoms; green mud. 



The only specimen from this Station agrees with the variety crebricostata of Sars, in 

 which the riblets are very numerous and similar in both valves. The distribution of this 

 species, recent and fossil, having already been- given by Jeffreys, I have merely to call 

 attention to the identity of Pecten idceus, Reeve, a fact hitherto unnoticed. 



Pecten gibbus (Linne). 



Ostrea gibba, Linne, Syst. Nat., p. 1147. 



Pecten gibbus, Lamarck, Anim. sans vert., ed. 2, vol. vii. p. 152. 



Pecten gibbus, Sowerby, Thes. Conch., vul. i. p. 52, pi. .\ii. fig.=. 1, 2, and pi. xiv. fig. 72. 



Pecten gibbus, Keeve, Conch. Icon., vol. viii. pi. ix. fig. 37, a-c. 



Habitat.- — Station 75, off" the Azores, in 450 fathoms; volcanic mud. 



Only one or two very small valves of this species were obtained. It is said to occur 

 on the west coast of Africa, and at the West Indies. 



