TELLINA. 371 



Even this consistent genus has a dozen synonyms, 

 two of them prior, and the rest subsequent to Liune's 

 time. 



A. Shell oval, nearly equilateral, concentrically laminated ; 

 lateral teeth conspicuous. 



1. Tellina balau'stina *,, Linne. 



T. balaustina, Linn. Syst. Nat. p. 1119 ; F. & H. i. p. 290, pi. xxi. f. 2. 



Body gelatinous, greyish-white : tubes clear white and trans- 

 parent ; orifices apparently not fringed or ciliated. 



Shell triangularly oval, or inclined to globular, ventricose, 

 thin, semitransparent, rather glossy : sculpture, regular, deli- 

 cate, and but slightly raised concentric laminae, which are easily 

 rubbed off or broken, more crowded at the sides, besides minute, 

 close-set, parallel striae in the interstices ; the whole surface is 

 also covered with microscopical and excessively fine but irre- 

 gular longitudinal striae : colour whitish with a faint tinge of 

 yellow, variegated by narrow streaks of a pinkish hue, which 

 radiate from the direction of the beaks and are more conspi- 

 cuous towards the margins ; these rays differ in number and 

 width, and frequently are broken and variously disposed, some- 

 times two or three beiug close tegether, and now and then con- 

 fluent : epidermis thin, filmy and iridescent, imparting to the 

 surface a silky lustre : margins semicircular on the anterior 

 side, regularly but more bluntly curved in front, slightly an- 

 gular on the posterior side, which is flexuous and separated 

 from the rest of the shell by an obscure and broad ridge ; dorsal 

 margin short, straight in the young and nearly so in the adult : 

 beaks small, incurved, and almost contiguous ; umbones some- 

 what raised : lunule lanceolate, deeply incised, with shelving 

 sides : ligament short, not very prominent, horncolour : hinge- 

 line more rounded than angular : hinge-plate slight, of mode- 

 rate breadth : teeth, in each valve two symmetrical, short, 

 erect, and diverging cardinals, the posterior of which in the 

 right valve and anterior in the left valve are bifid or double ; 

 laterals, one on each side in both valves, remote and laminar, 

 more developed in the right than in the left valve: inside 

 glossy, tinged with orange, microscopically wrinkled and lon- 



* Colour resembling lhat of a pomegranate flower. 



