78 Zoological Society . 



right. Umbilicus, very deep and suddenly narrowed. Labral lamella , 

 very strongly produced close to the labrum above, less prominent 

 round the umbilicus. Operculum, slightly concave in the middle, 

 with a deep broad margin all round, very fine granulations in the 

 hollow, with (?) four very fine distant carinse crossing diagonally 

 from right above to left below. 



Height 0-04, greatest breadth 0*066, least breadth 0-053. 



Named in compliment to the memory of the late Mr. David Dyson 

 of Salford, so well known for his zoological researches in Central 

 America, Venezuela, &c. 



WiLKiNSON^A Hanleyana, Chitty. 



Hab, Pool's Rock, Hanover. 



Form, subdiscoidal, or very depressed conic. Colour, pale horn. 

 Sculpture, lines of growth, wide apart : 3 strong spiral carinse ; 

 4th, stronger ; 3 strong ; 8th, stronger ; 3 strong ; 1 2th, stronger ; 

 3 strong ; 1 6th, stronger ; 2 strong ; 1 9th, stronger ; and 4 strong 

 round the umbilicus. On the upper whorls, 3 strong ; 1 stronger ; 

 and 3 strong. Spire, slightly elevated, with straight or very slightly 

 concave outlines. Whorls, 3^, well rounded with light suture. 

 Aperture, much constricted behind the labrum, and then much di- 

 lated ; depressed above and expanding below ; subsemicircular. La- 

 brum, double, slightly produced above ; pectinated and slightly scol- 

 loped by the five stronger carinse ; attached to the body-whorl and 

 produced at an angle of about 70° ; slightly thickened and reflected. 

 Labium, much lower than the plane of the labrum above ; less so, 

 below, moderately detached from the body-whorl ; rather curved at 

 both extremities. Umbilicus, shallow and broad, not affected by the 

 labral lamella, which is fine and narrow throughout. Operculum ? 



Height 0-041, greatest breadth 0-061, least breadth 0-047. 



Named in compliment to Sylvanus Hanley, Esq., author of * Bri- 

 tish Shells,' &c. 



WiLKiNSON^A Bensoniana, Chitty. 



Hab. Roaring River, Westmoreland. 



Form, subdiscoidal. Colour, rather dark brown. Sculpture, six 

 prominent sharp spiral carinse intermingled with eighteen less strong : 

 on the upper whorls, one strong between about six less strong. 

 Spire, very little elevated, with slightly concave outlines. Whorls, 

 3|, slightly rounded with a very light suture. Aperture, semicir- 

 cular, depressed above in the uppermost third, much expanded 

 below. Labrum, much and pointedly produced above, at an angle 

 of about 75° from the body- whorl, white, slightly thickened and re- 

 flected, angulated, not pectinated, by all five points of the sharper 

 carinse. Labium^ rather curved below, much detached from body- 

 whorl, on a plane with the labrum at the lower end, much below it 

 above. Umbilicus, rather deep and broad. Labral lamella, regu- 

 larly produced, strong but narrow, subangularly pointed close at the 

 labrum. Operculum, moderately concave, serpentine on the labial 

 side, with a groove on the labral side. 



Height 0-027, greatest breadth 0-049, least breadth 0*038. 



