128 Mr. W. H. Benson on the genus Scaphula. 



the Tenasserim species, and the variation of characters, will 

 permit of a more correct diagnosis of the genus than was possible 

 from the typical species, specimens of which are exceedingly 

 rare. No conchologist has collected in Bundelkhund since the 

 period of my residence in that province, and a search which I 

 made for specimens of the shell, during a hurried visit to Banda 

 in 1844, proved fruitless. 



Scaphula, Benson. Zool. Journ. 1834, vol. v. p. 464-5. 



Testa seqiiivalvis, valde insequilateralis, subtrapeziformis, carina valida 

 ab umbonibus distantibus usque ad marginem posteriorem et 

 basalem extendente ; cardo rectilinearis, medio tenuis, ad extre- 

 mitates sulcidentatas latior, dentibus anterioribus 4, crenulatis, 

 minutis obliquis, posterioribus lamellatis, parallelibus, intus ob- 

 hque descendentibus, 4 ad 6, prime obliquis, demum transversis, 

 raro bifurcatis, munita ; ligamentum exterius, rhombiforme, inter 

 umbones situm ; epidermis tenuis vel crasse lamelloso-rugosa ; 

 muscidi adductoris impressio antica unica, posteriores duse sub- 

 distantes quorum inferior oblongo-quadrata ; pallii impressio 

 Integra. 



The genus is at once distinguished from its nearest allies, 

 Area and Cucullaa, by the hinge being linear and edentate in 

 the middle and for the greatest part of its length, and by the 

 form and position of the teeth at the extremities ; the laminar 

 posterior ones, which are sometimes ramose, running obsoletely 

 and obliquely into the interior of the shell. The two distinct 

 adductor muscular impressions, and the squareness of the lower 

 one on the posterior side in both species, are peculiar features 

 supporting the claims of the type to generic distinction. 



Scaphula Pinna, n. s. 



Testa elongato-triangulari, subtrapeziformi, extus sub epidermide 

 albida, intus cserulescente, antice angusta, extremitate subacute an- 

 gulata, arcuatim descendente, postice subalata, expansa, extremitate 

 supernearcuata, infra rectangulari; carina acuta, compressa ; pagina 

 postica majori subremote, antica confertim concen trice sulcata, 

 utrinque radiatim striatula ; epidermide fusco-nigra, crasse rugoso- 

 lamellata, marginem nigrescentem excedente ; musculi anterioris 

 impressione ovato-rotundata, posterioribus duabus, superiori sub- 

 cardinali elongata, angusta, inferiori elongato-quadrata. 



Long. 11, alt. 5, crass. 6 mill. 



Habitat in flumine Tenasserim. 



The River Tenasserim has a course through nearly three 

 degrees of latitude, between the coast ranges and the high 

 interior chain which forms the British boundary towards Siam, 

 before it turns suddenly towards its embouchure at Mergui. 



The appearance of a slight iridescence on the bluish enamel 



