258 



MOLLUSCA FROM THE CRAG. 



CULTELLUS TENUIS, Philippi. Tab. XXV, fig. 2, a d. 



SOLEN TENUIS. Phil. En. Moll. Sic., vol. i, p. 6, pi. l,fig. 2, 1836. 

 Id. En. Moll. Sic., vol. ii, p. 5, 1844. 



GENUIS. Nyst et West. Nov. Rech. Coq. Foss. d'Anv., p. 3, No. 4, 1839. Mis- 



print. ? 



TENUIS. Nyst. Coq. Foss. de Belg., p. 46, pi. 1, fig. 5, 1844. 

 CULTELLUS CULTELLATUS. S. Wood. Catalogue, 1840. 



J. Sowerby. Min. Conch., t. 642, figs. 5 8. 



Spec. Char. " Testa oUongo-tineari, recta, utrinque rotundatd, tenuissimd ; cardinibus 

 lateri antico approximates, in valvuld dextrd bidentatis, in sinistrd tridentatis." Philippi. 



Shell linearly oblong, straight, rounded at both extremities, very thin ; very inequi- 

 lateral ; two cardinal teeth in the right valve, and three in the left. 



Length, lj inch. 



Locality. Cor. Crag, Button. 



Red Crag, Walton Naze. 



This shell is rare in my cabinet. Two specimens of the right valve, and one of the 

 left, from Walton-on-the-Naze, are all that I have seen. 



The Coralline Crag at Sutton has furnished numerous fragments sufficient to justify 

 the belief in their identity with the Belgian fossil and the Mediterranean species, 

 but it is not S. pellucidus, Penn. M. Philippi's figure shows a much greater 

 inequilaterality than our fossil, one side being four times the length of the other 

 (probably an error of the artist). In the Crag shell the proportions are as two and 

 a half to one. 



It is somewhat broader or higher on the siphonal side, and equally rounded 

 at both extremities. The right valve is furnished with two cardinal teeth, the 

 anterior one is vertical and compressed, the other larger and diverging. In the left 

 valve are three teeth, the centre one is large, and deeply cleft or bifid, one por- 

 tion decumbent, almost parallel with the ligamental fulcrum. The muscular marks 

 in my specimens are indistinct. 



The shell to which this appears to bear the nearest relationship (judging alone 

 from the drawing of the exterior), is one obtained in the Corea, figured by Messrs. 

 Reeves and Adams (Solen albida), e Voy. of the Samarang, 1850/ p. 84, pi. 23, fig. 15. 



THRACIA, Leach, MS. 1819. 



MYA (sp.) Montague, 1803. 

 LIGULA (sp.) Id. 1808. 

 AMPHIDESMA (sp.) Lamk. 1818. 

 AKATINA (sp.) Id. 1818. 



IXARTIA. Leach, MS. 1819. 

 THRACIA. Blainv. 1825. Rang. 1829. 



OSTEODESMA (sp.) Blainv. 1825. 

 ODONCINETUS. Da Costa, 1829. 

 CORIMYA (sp.) Agass. 1842. 

 ODONTOCINETA. Id. 

 CINETODONTA. Herrm. 1847. 



