REPORT ON THE LAMELLIBRANCHIATA. 91 



having been met with in tlie Mediterranenn, at Madeira, and off the Norwegian and 

 Britisli coasts. 



Psammohia pidcherrima, Deshayes. 



Psammohia pulchern'ma, Deshayes, Proc. Zool. Soc. Lond., 1854, p. 325. 

 Pganmiohia pulchcrrinia, Reeve, Conch. leoii., vol. ,k. iig. 46. 



Habitat. — Station 172, off Nukalofa, Tongatalju, in 18 fathoms; coral mud. 



The habitat of this species lias hitherto Ijeeu unknown. The type shell tigured liy 

 Reeve is only half-grown, and on this account has been described as " thin." The .single 

 specimen obtained by the Challenger is probably adult, and at this age is rather a thick 

 shell in comparison with many other species of this genus. It is 31 mm. long. 15 high, 

 and 8^- in diameter. 



It is of a yellowish tinge ornamented with several slightly arcuate .sanguineous rays, 

 and tinted at the hinder extremity with pale rose. The interior is painted somewhat 

 like the outside, except that the rays are rather more purplish and clouded. The valves 

 are very slightly inequilateral, the anterior side being the shorter, but not so dispropor- 

 tioned as represented by the figure in the Conchologia Iconica. They are transversely 

 elongate, only half as high as long, moderately convex, having the anterior two-thirds of 

 their surface coarsely obliquely sulcate and ridged, the ridges being broader and the 

 intervening grooves narrower than posteriorly, where they terminate abruptly at the 

 first of the oblique radiating costse which adorn the hinder pqrtion of the surface. These 

 are ten in number, gradually thicken as the shell enlarges, are separated by deep furrows, 

 and in the early stages of growth or towards the umbones are more or less nodulose. 

 The single tooth of tlie left valve and the posterior in the right are somewhat cleft at 

 the tip, the front one in the latter valve being broad and oblique. The pallinl sinus is 

 large, deep, rounded at the end, and extends beyond the centre. 



Psammohia castrensis (Spengier). 



Solen castretisis, Spengier, Chemnitz, Conch. Cab., vol. xi. p. "201, pi. cxcviii. figs. 193.5, 1D36. 

 Solen castrensis. Wood, Index Test, pi. iii. fig. 25. 

 Psammohia castrensis, Hanley, Cat. Biv. Shells, p. 59. 

 Psammohia castrensis, Reeve, Conch. Icon., vol. x. fig. 32. 

 Psammohia oriens, Deshayes, Proc. Zool. Soc. Lond., 1854, p. 318. 

 Psammohia oriens. Reeve, Conch. Icon., vol. x. fig. 1. 

 ' Psammohia oriens, Dunker, Index Moll. Mar. Japon., p. 186. 



Habitat. — Station 172, off Nukalofa, Tongatabu, in 18 fathoms ; coral mud. 



A single specimen from this locality, dredged in a dead condition, differs from the 

 tjrpical form in having the po.sterior end of the shell more strongly sculptured than usual. 



