The Hon. E. Chitty on the Stoastomidse. 75 



from left to right, the labral side finely plaited, the lower left end 

 expanding broadly, and folding over the lower part of the labium 

 in thin plaits or laminae ; which plaits are continued on the lower 

 side of the operculum. A very interesting shell. 



Height 0*039, greatest breadth 0074, least breadth 0*053. 



Named in honour of Sir Robert Schomburgk, the celebrated 

 traveller in Guiana, and great naturalist, &c. 



WiLKiNSON^A Abbottiana, CMtty. 



Hab. ? Hanover. 



Form, subdiscoidal. Colour y white, subtransparent, shining. 

 Sculpture, five very strong spiral carinae, with, at the periphery, two 

 highly microscopic, scarcely visible, intervening between the strong 

 lines ; three rather stronger, below the lowest strong carina round the 

 umbilicus ; one strong on the upper whorls. Spire, much depressed, 

 with convex outlines. Whorls, 4, very slightly rounded, with a light 

 suture. Aperture, extraordinarily produced from the body-whorl, 

 rather constricted far away from the labrum, and rather cupped 

 inwards to the labrum ; flattened- above, expanded and depressed 

 below, semielliptical. Labrum, extraordinarily produced and de- 

 pressed at the uppermost strong spiral carina, slightly scolloped and 

 pectinated at and by the other strong carinas, reflected and thickened 

 slightly. Labium, widely detached from the body- whorl, very little 

 curved to the right below, very much below the plane of the labrum. 

 Umbilicus, shallow and broad^ Labral lamella, slightly and angu- 

 larly spread out close to the labrum, then thin and narrow and not 

 concealing the umbihcus. Operculum, most extraordinary, and who 

 can describe it ? ! Very deeply concave in the middle,, with a broad 

 raised margin all round, very broad and much rounded on the labial 

 side, which has a largely developed tooth-like horizontal plait or fold 

 half-way down it descending into the hollow, and a much larger one 

 proceeding from the lowest labial side, flowing, as it were, to the left 

 well over the labial side, and also over the labium, not concealing 

 the lowest part of the operculum, but showing the lowest part of 

 the labial side to be broad and spreading, — trumpet-shaped. Un- 

 fortunately I possess but two specimens, only one having the oper- 

 culum, which is so firmly fixed in the shell that I dare not further 

 attempt its extraction, and therefore I cannot further examine its 

 extraordinary structure. 



Height 0*034, greatest breadth 0*066, least breadth 0*049. 



Named in compliment to Captain George Abbott, of the R.W.I. 

 Steam Mail Company's Service (at present commanding the * Mag- 

 dalena'), for his great care and attention in procuring and pre- 

 serving specimens of natural history for the Zoological Society of 

 London. 



WiLKiNSONjEA Jardineiana, Chitty. 



Hab. Swift River Head, St. George's. 



Form, subdiscoidal. Colour, very pale horn. Sculpture, lines of 

 growth visible ; seven strong spiral carinse, without intervening fine 

 ones ; three strong, on upper whorls. Spire, slightly elevated, with 



