326 



SOLARIELLA. 



are three strong closely-beaded threads, the inmost of which defines 

 the umbilicus, within which is a finer beaded thread, and, deep 

 inside a ridge. Longitudinals all the upper whorls are crossed by 

 strong straight ribs, forming tubercles where they cross the spirals, and 

 leaving deep square hollows between. Only on the penultimate 

 whorl do these become oblique and feebler, till toward the mouth 

 they are narrow, weak, crowded, and broken. Besides these, the 

 whole surface is roughened with small, coarse, irregular lines of 

 growth. Color dead white. Spire high and conical, but the tumidity 

 of the last whorl, especially towards the mouth, greatly detracts from 

 this ; it is slightly scalar. Apex small, whorls 6, of slow increase 

 till the last, angular, projecting out squarely from the suture, 

 flattened on the contour, and contracted below the carina; but the 

 last whorl is rounded, tumid, and toward the mouth, expanded. The 

 base is rounded, but not inflated. Suture very deep and strong, 

 from the overhanging of the carina above it. Mouth extremely 

 oblique, perfectly round but for a slight flatness across the body and 

 an angulation at the insertion of the outer lip and also at the junc- 

 tion of the pillar-lip to the body ; pearly within. Outer lip very 

 slightly descending at its insertion, then in its sweep rising a little ; 

 it is scarcely angulated at the lower carina and at the point of the 

 pillar, but it is a little sinuated at that part ; it is thin on the edge, 

 but is thickened within by a pretty strong pearly callus and outside 

 by a slight rounded marginal varix. Pillar-lip is hollowed back into 

 the pillar in a sinus, and is sharply reverted, so as to leave a minute 

 but deep furrow r behind it ; this reversion ceases just before it reaches 

 the umbilical thread, and forms a minute tooth at that point. 

 Umbilicus wide and pervious, and narrowed within ; its slope is 

 scored with minute sharp curved lamina?, the remains of the old 

 edges of the pillar-lip sinus. 



Alt, -18, diam. -27, least '17. Mouth, height, '1, breadth '1 in. 

 ( Watson.) 



In general aspect this is very like Trochus (Margarita) gemmulosa, 

 A. Ad., but that species has the spire lower, the suture distinctly 

 depressed, the sutural furrow is beset with close radiating striae, the 

 spiral threads are more numerous and crowded, the pointed tubercles 

 on these are more frequent, aud there is no varix on the outer lip. 

 This last is a feature which gives a great peculiarity to this species ; 

 but the thickening and the patulousness of the lip are not sufficient 



