386 tellinidjE. 



C. Shell oblong, inequilateral, angulated, and slightly gaping 

 at the posterior end, concentrically striated ; lateral teeth 

 more developed. 



7. T. dona'cina*, Linne. 



T. donacina, Linn. Syst, Nat. p. 1118 ; F. & H. i. p. 292, pi. xx. f. 3, 4, 

 and (animal) pi. K. f. 4. 



Body oblong, compressed, white : mantle not fringed, bnt 

 finely dentated (Clark) (" conspicuously fringed," Forbes and 

 Hanley) : tabes long and slender, with plain orifices, marked 

 at their sides by whitish lines, which appear to represent rows 

 of cilia : (fills suboval, nearly of the same size, pale brown, 

 smooth outside, and striated inside by about 30 delicate vessels 

 of the branchial circulation : palps subtriangular, narrow, lon- 

 gitudinally furrowed, but otherwise smooth outside and pecti- 

 nated within : foot pure white, flat, broad, long and pointed. 



Shell triangularly oblong, compressed, of a moderate thick- 

 ness, opaque, more or less glossy : sculpture, numerous fine 

 concentric and rib-like strioe, which are more close-set in 

 the young, and consequently cover the umbonal area in the 

 adult, besides intermediate and more delicate striae, only ob- 

 servable by means of a high magnifier, and then chiefly in the 

 interstices of the larger striae : colour yellowish-white, rarely 

 saffron, ornamented with bright pink longitudinal rays and a 

 more conspicuous but shorter streak of a deep rosy or carna- 

 tion hue just below the beak in each valve on the ligamental 

 side ; the rays are generally broken or interrupted, and fre- 

 quently confluent, and they vary in number and arrangement, 

 being often in pairs ; in some specimens the ground-colour is 

 rosy and the rays white : epidermis fibrous, light reddish- 

 brown, seldom retained except in the young : margins rounded 

 in front, with an oblique and somewhat flexuous curve to the 

 posterior end, also rounded and wedge-shaped on the anterior 

 side, truncate and flexuous on the posterior side, which ends 

 in a blunt angle ; dorsal margins on both sides straight, the 

 anterior twice as long as the posterior, forming between them 

 at the point of junction a well-defined obtuse angle ; the pos- 

 terior side slightly gapes, and has an obscure ridge in each 

 valve, extending from the beak to the point of the lower angle : 

 beal-s small, sharp, and contiguous, turned towards the pos- 

 terior side : ligament large, prominent, dark horncolour, sepa- 



* So named from its resemblance to a Donax. 



