SOLARIELLA. 



329 



oblique, round. Outer lip sharp but strong, porcelaneous on the 

 edge, brilliantly nacreous within ; it descends very slightly. Pillar- 

 lip thick, white, bent nearly to the point of the pillar over the um- 

 bilicus. It would be reverted but for the great thickness of the 

 spiral pad, which comes twining up behind it out of the umbilicus, 

 and out of which, at the point of the pillar, it forms a flat, 

 triangular, tooth-like expansion. Umbilicus a minute spiral hole, 

 which twists in between the overlying pillar-lip and the umbilical 

 pad ; the edge is corrugated with the old lines of the lip. 



Alt. 0%33 in., diam. 0'4, least 0'3. Penultimate whorl, O'l. Mouth, 

 height 0-2, breadth 0'17. ( Watson.') 



This species somewhat resembles in form Trochus tumidus, Mont. ; 

 but, apart from differences of texture, color, and sculpture, it is, 

 than that, less conical, more scalar, the suture is much more im- 

 pressed, and the whorls are more immersed. From Trochus (Mar- 

 garita) rhina, Wats., it differs in the whorls being much more 

 .tumid and the general form less conical. From Trochus (Mar- 

 garita) pompholugotus, Wats., it differs in the last whorl being far 

 less tumid and out of proportion to those which precede. In con- 

 trast with Trochus . (Margarita) dnopherus, Wats., the pad on the 

 pillar-lip is here rather on the outside, with the lip flattened out 

 upon it, while in that species the thickening is on the inside, filling 

 up the lip. There is a general resemblance to Trochus marginu- 

 latus, Phil., but the whole sculpture is quite different ; especially on 

 the base that species has a sharp umbilical carina, and a wide 

 funnel-shaped though shallow umbilicus. Taken in general, it most 

 of all resembles Trochus (Margarita) varicosus, Migh. (=Trochus 

 polaris Daniels.). Compared to that this species is stronger in the 

 shell, and much more distinctly sculptured. That other is higher 

 in the spire, narrower, with a higher and more tumid body whorl ; 

 the whole sculpture, though quite of the same type, is feebler, the 

 base is more flatly conical, more radiatiugly striate with a large 

 funnel-shaped umbilicus which has a double cord round its edge ; 

 the embryonic apex is much larger and coarser, and is altogether 

 more prominent, and consists of nearly one whorl and three-quarters, 

 and the whole shell is in every way larger, with of whorls against 

 6 here. ( Watson.') 



Fayal, Azores, 450 fms. 



T. (Margarita) azorensis WATSON, Journ. Linn. Soc. Lond. xiv, 

 p. 710 ; Challenger Rep., Gasterop., p. 88, t. 5, f. 12. 



