242 



The peculiar elevated sulci on the dorsal areas, at once distin- 

 guish it from all the allied species, 

 Tumbez, Peru. 



37. Tellina alternata (pi. Ixi. f. 159.) Say, Jour. Ac.Plul. 

 vol. ii. p. 275 ; Amer. Conch, t. 65. f. 1 ; Hani. Des. Cat. p. 66. 

 sup. 1. 14. f. 9. 



T. testa oblongo-elongata, solidiuscula, nitida, compressiuscula, 

 alba aut albo-flavescente, (intus flava) ; concentrice sulcata, sulcis 

 remotis, profundis, ad costam umbonalem obsoletissimam alternatim 

 evanescentibus ; margine ventrali subrecto; dorsali antice decHvi 

 convexiusculo, postice recto et multum dechvi; latere postico 

 manifeste longiore, ad extremitatem rotundato ; antico cuneiformi > 

 Ugamento prominente ; flexura inconspicua ; dentibus iisdem ut in 

 I'uniced. 



Elongated-oblong, rather solid, and somewhat compressed, of a 

 glossy opaque wliite or yellowish wlute, grooved concentrically with 

 rather distant deeply impressed sulci, wliich alternately disappear 

 in crossing the nearly obsolete mnbonal ridge ; ventral edge nearly 

 straight ; anterior side much the longer, rounded at its extremity, 

 its dorsal edge moderately sloping in a convex line ; posterior side 

 cuneiform, its dorsal line being straight and greatly sloping ; liga- 

 ment prominent; fold indistinct; inside wliite, the teeth as in 

 Tunicea. 



In the only specimen I have ever seen of this shell, the striae are 

 closer in one valve than in the other. In general appearance the 

 shell is extremely like Striata. 



South Carolina. 



38. Tellina rubescens (pi. Ix. f. 153.) llanley, Zool. Proc. 

 1844. 



T. testa T. Striata et Punieea simillima, ab hac autem differt, 

 testa tenuiore anticse emarginationis experte, ab ilia natibus obtu- 

 sioribus et extremitate postica minus attenuata ; ab utr^upe, super- 

 ficie nitidissima, ligamento infosso, margineque dorsali convexiore 

 et utrinque subsequahter decHvi ; sulcis in utraque valvula postice 

 obsoletis ; dentibus ut in Pimiced, sed minimis, inconspicuis. 



Most closely aUied to Striata and Punicea, but difiering from 

 the former by the greater obtuseness of its beaks, and the lesser 

 attenuation of its liinder extremity ; from the latter by its more 

 delicate texture and the absence of any anterior emargination ; 

 from both, in the sunken ligament, the greater convexity and more 

 equal slope of the dorsal edge. The sulci are obsolete posteriorly 



