602 BET. E. BOOG WATSON ON THE 



put into tlie genus Trochus in any of its divisions. In form it re- 

 sembles most of all one of the "West- Indian operculated pulmonates, 

 such as Alcadia, while its exquisite nacre, its cancellated sculp- 

 ture, its reflexed thickened lip, its nacreous umbilical pad, and 

 its perpendicular externally mucronated pillar, separate it in 

 the strongest way. In these circumstances I have yielded to the 

 strongly expressed opinions of judges so trustworthy as Dr. 

 Kobelt, of Erankfort, and Mr. Dall, of "Washington, and take 

 this as the type of a new genus. 



1. GrAZA DJEDALA, W. (laitaXos, variegated.) 



St. 174. August 3, 1874. Kandavu, Eiji. Lat. 19° 10' S., long. 



178° 10' E. 610 fms. Glohigerina-ooze. 1 specimen. 



SJiell. — Depressedly globose, with a convexly conical spire, thin, 

 translucent, horny, nacreous in its whole texture, and irides- 

 cent on the surface, with a slightly reverted and narrowly 

 thickened lip, a thin-edged twisted pillar, the point of which 

 runs out into a bluntly mucronated angle. Sculpture. Lon- 

 gitudinals — the whole surface is covered with strong, puckered, 

 oblique lines of growth, which are sharp-edged, but flat- 

 tened, rather regular, with many minuter ones in the inter- 

 vals. The longitudinals are cross-hatched with spirals which 

 are stronger and more regular but not perfectly uniform, 

 consisting of square threads and furrows of equal breadth, 

 and both scored by the longitudinals ; on the earlier whorls 

 these spirals disappear before the longitudinals do ; and on 

 the base they become on the outside feebler, closer, and finer, 

 in the middle broader and flatter, and stronger again toward 

 the centre of the shell. Colour a delicate yellowish, with a horny 

 translucency and exquisite iridescence, which under the lens 

 appears brilliant. Spire high and slightly scalar. Apex very 

 small, flatly rounded, the embryonic 1 J whorl very slightly pro- 

 jecting. Whorls 7, of gradual increase, well rounded, the last 

 slightly angulated below, and on the base flattened, but rather 

 less so towards the mouth, where there is a slight con- 

 traction and downward turning of the whole whorl, without, 

 however, any descending of the lip at its junction with the body. 

 Suture very distinct, but not impressed. Mouth rather large, 

 very oblique, semioval. Outer Up reflected and thickened by 

 a strong but narrow, equal, rounded, white pearly callus, which 

 almost disappears just at the upper corner, and which has a very 

 slight furrow round its margin ; it does not descend at all. 



