392 TELLINIDiE. 



1. Psammobia tellinel'la*, Lamarck. 



P. tellinella, Lam. An. sans Yert. v. p. 515 ; F. & H. i. p. 277, pi. xix. f. 4, 



and (animal) pi. K. f. 1. 



Body oblong, pure white : mantle dentated in front and 

 fringed behind from the beaks to the tubes: the latter are 

 moderately long, tapering, and divergent ; the exeurrent tube 

 is the more slender, and curved upwards, marked lengthwise 

 with eight fine lines of intense frosted white running from one 

 end to the other, and having its orifice encircled with exceed- 

 ingly minute and short white cirri ; orifice of inrurrent tube 

 furnished with six similar cirri and intermediate shorter ones : 

 gUU suboval, pale brown, hanging obliquely, and coarsely 

 striated on both sides; upper very small : palps rather long, 

 subtriangular, pointed, pale brown, outwardly smooth, and 

 inwardly coarsely pectinated transversely, not furrowed as in 

 TeUina donacina : foot fiat, sharp-edged, slightly bent, and 

 lanceolate at the point. 



Shell oblong, compressed, rather thin than solid, opaque, 

 slightly glossy: sculpture, very delicate and close-set but 

 somewhat irregular concentric striae, with occasional and more 

 strongly-marked lines of growth ; the concentric or transverse 

 striae are crossed by others, which are longitudinal and equally 

 tine, but sometimes become larger and almost rib-like on the 

 posterior slope ; in fresh specimens the surface is thus faintly 

 decussated, but the longitudinal stria? always predominate: 

 colour yellowish- white tinged with violet or fiamecolour, varie- 

 gated by rays of either of those hues, or of pink, and diver- 

 sified by short longitudinal streaks or wavy and irregular lines 

 of the same tint; usually on the anterior (and frequently also 

 on the posterior) side of the beaks are short but broadish rosy 

 streaks as in TeUina donacina ; rarely the colour is uniform 

 milk-white or purple : epidermis thin, pale yellowish-brown, 

 generally obliterated : mart/ ins slightly and obtusely curved in 

 front, more acutely so on the anterior side, and bluntly pointed 

 at the posterior extremity, from which the margin in each 

 valve slopes with different degrees of curvature to the beak, 

 the deflection on each side of the umbo being nearly equal ; 

 the posterior side is somewhat angular, and both sides are 

 wedge-like: beaks small, sharp, contiguous, turned towards 

 the posterior side : ligament short, prominent, at first of a 



* Resembling n small kind of T ' 



