252 



internally, with the umbones diaphanous and of a tawny orange- 

 colour ; nearly smooth or merely substriated concentrically towards 

 the somewhat arcuated ventral margin ; dorsal edges convex, equally 

 and moderately sloping on either side ; beaks obtuse ; fold distinct; 

 umbonal ridge almost obsolete ; posterior side obtuse and attenu- 

 ated ; ligament extremely narrow, sunken ; lateral teeth distinct, 

 the anterior slightly the nearer. 



Cagayan, Misamis, Mindanao ; St. Nicolas, Zebu. 



More oval than the three succeeding aUied species. 



55. Tellina piNGUis (pl.lvi.f.34.) Hanley, Zool. Proc. 1844. 



T. testa parva, rotundato-ovali, tenui, subinaequivalvi, subsequi- 

 laterali, nitida, convexa aut subventricosa, intus extusque albida 

 (rarius incarnata), laevigata (nonnunquam concentrice substriata) ; 

 margine ventrali arcuato, dorsali utrinque convexo et subajquahter 

 declivi; extremitate postica obtusa; flexura distinctaj natibus 

 minimis; costa umbonaM fere obsoleta; hgameuto angustissimo, 

 infosso ; dentibus ut in Nii^ce. 



Eounded-oval, thin, rather inequivalve, nearly equilateral, from 

 convex to subventricose, both externally and internally whitish, 

 or more rarely flesh-coloured, smooth, (sometimes concentrically 

 substriated) ; the ventral edge arcuated ; the dorsal on each side 

 nearly equally sloping and convex ; beaks minute ; fold distinct ; 

 umbonal ridge almost obsolete; posterior end obtuse; ligament 

 extremely narrow and sunken ; teeth as in Nux. 



St. Nicolas, Zebu. 



By its more orbicular outline it may be distinguished from Nux 

 and Casta. It is still more closely allied to Robusta, but its tenuity, 

 more obtuse liinder extremity, and the greater convexity and less 

 sudden slope of the dorsal edges, suffice for its separation. 



56. Tellina EOBUSTA (pi. Ivi. f.2, 3.)5a«%,Zool.Proc.l844. 



T. testa parva, rotundato-subtrigona, soHda, subinsequivalvi, 

 subsequilaterali, ventricosa, nitida, aut albo-flavescente, aut pallide 

 rosacea, sublsevigata (plerumque inferius remote substriata) ; mar- 

 gine ventrali valde arcuato, dorsali utrinque subrecto et valde de- 

 cHvi; latere postico attenuate, fere subrostrato, ad extremitatem 

 acuminato; ligamento angustissimo, infosso; natibus distinctis, 

 prominentibus, et recte incurvatis; umbonibus tumidis; flexura 

 distincta ; costa umbonah fere obsoleta ; lunula parva ; superficie 

 interna, plerumque sub umbonibus, flavida aut rosea ; dentibus ut 

 in Nuce. 



