208 MR. H.ADAMS ON LAND AND MARINE SHELLS. [Feb. 18, 



Bulimus (Drym^etjs) rawsonis, sp.nov. ("Plate XXIII. fig. 12.) 



B. testa subimperforata, elongato-ovata, tenui, oblique longitudina- 

 liter striolata et striis minutissimis cincta, nitida, alba, ad apicem 

 et ad basin aurantiaca ; spira elevato-conica, apice acutiusculo, 

 sutura impressa ; anfr. 6^, convexiusculis, ultimo spiram sub- 

 (squante, basi vix attenuato ; apertura parum obliqua, oblongo- 

 ovali; perist. simplici, recto, margine columellari superne reflexo, 

 perforutionem fere occultante. 



Long. 24, diam. 10 mill. 

 Hab. Tobago {Mr. Rawson). 



Corbula pygm^ea, sp. nov. (Plate XXIII. fig. 13.) 



C. testa solida, subovata, ventricosa, cequilaterali, sulcis concentricis, 

 minime profundis sculpta, albida ; umbonibus medianis, incon- 

 spicuis; latere antico rotundato ; latere postico angulato ; margine 

 ventrali arcuato ; declivitate umbonali obtuse angulata. 



Long. 2|, alt. 2, lat. 1 mill. 



Hab. Persian Gulf {coll. M' Andrew). 



Tellidora pellyana, sp.nov. (Plate XXIII. fig. 14.) 



T. testa subtriangulari, incequilaterali, utrinque convexiuscula, so- 

 lidula, concentrice tenuissime lirata et leviter plicata, plicis 

 ad latus posticum attenuatis, prominentibus, albida; umbonibus 

 postmedianis, acutis ; margine dorsali antice subincurvato , postice 

 subrecto ; margine ventrali convexo, postice sinuato ; flexura 

 distincta. 



Long. 10, alt. 9, lat. 2£ mill. 



Hab. Persian Gulf {coll. M c Andrew). 



Thyella lamellosa, sp. nov. (Plate XXIII. fig. 15.) 



T. testa ovato-triangulari, solidula, modice convexa, fere cequi- 

 laterali, lamellis erectis numerosis concentricis et striis confertis 

 minutissimis radiantibus sculpta; margine dorsali antice incur- 

 vato, postice convexo ; margine ventrali arcuato, postice paulum 

 sinuato. 



Long. 12, alt. 9, lat. 6 mill. 



Hab. Mauritius {coll. H. Ad.). 



Thyella hargravesi, sp. nov. (Plate XXIII. fig. 16.) 



T. testa triangulari, solidiuscula, subventricosa, aquilaterali, lamellis 

 distantibus irregularibus concentrice et striis exilibus confertis ra- 

 diatim sculpta ; latere anteriore arcuato ; latere postico convexo ; 

 margine ventrali postice valde sinuato. 

 Long. 6^, alt. 5|, lat. 3£ mill. 

 Hab. New Hebrides {coll. Hargraves). 



The genus Thyella was founded by me some years since upon a 

 small shell in Mr. Cuming's collection, and stated to have affinity 

 with Semele. It is also near Montrouziera, Souvevbie ; but that 



