344 PROCEEDINGS OF THE ACADEMY OF [1890. 



Euchelus alabastrum Keeve. 



This shell has the globose-conical form common to the more ele- 

 vated species of the genus. The aperture occupies less than half the 

 altitude of the shell. It is umbilicate, solid and thick, the surface 

 lusterless and chalky-white having a few dark dots 

 on the spiral carinse. The sculpture consists of 

 elevated spirals, flange-like and curling upward, with 

 a very beautiful fine crenulation on the concave 

 upper surfaces of the flanges. The third spiral is 

 Fig. 2. at the periphery of the body-whorl ; below it there 



are six spiral cords, the lower four exquisitely serrated, the last 

 one within the edge of the funnel-shaped umbilicus. The whorls of 

 the spire are tri-carinate ; sutures excavated. The mouth is very 

 oblique, closely lirate within ; columella nearly straight, toothed 

 near the base. 



Alt. 17, diam. 16.1 mm. ; oblique alt. of mouth 13 mm. 

 This form was badly described by Reeve in P. Z. S. 1854, p. 209. 

 It has not been noticed by subsequent authors. As it is so well- 

 marked a species, it seems worth while to have a recognizable de- 

 scription and figure published. The habitat is Diego Garcia, a little 

 island near Mauritius. 



The specimen figured was given me by Mr. C. W. Johnson. 



