316 SOLARIELLA. 



I'emote rounded tubercles, defining the umbilicus, within which is a 

 very slight furrow and an ill-defined ridge. Longitudinals — the 

 apical whorls are ribbed, but the ribs gradually break into the 

 scarcely connected tubercles of the last whorl. The lines of growth 

 are hardly perceptible, except on the base. Color pure white when 

 Aveathered, but apparently slightly brownish when fresh, with a pearly 

 nacre below the thin calcareous surface-layer. Spire high, very 

 slightly scalar. Apex sharp, minute, flattened on the one side, with 

 the ver\^ small embryonic 1 \ whorl rising sharply on the other. 

 Whorls 7, of regular increase ; the last is small, from the large part 

 of it cut out by the umbilicus ; they are flatly conical and slightly 

 scalar. Suture linear, but strongly defined by the right-angled 

 junction of the whorl. Mouth oblique, much inclined to the axial 

 line, rectangularly rounded, the pillar and outer lip being parallel. 

 Outer lip thin and broken, not descending. Pillar-lip shortly but 

 flatly bent over the umbilicus, and here it is patulous and sinuated, 

 it then advances in a straight line toward the base. It is toothed in 

 the middle by a strongish spiral protuberance at which point it 

 projects; but from this to the junction with the base it is thin and 

 retreats. Umbilicus very large, funnel-shaped and pervious. 



Alt. 0-27 in.; diam. OS, least 0-25. Mouth, height O'l, breadth. 

 0-15 in. (Watson.) 



This very beautiful species is well defined by its exactly conical 

 form and very large umbilicus, which cuts the whole body out of the 

 inside of the last whorl, narrowing the base to an extraordinary 

 extent. The young shells are excessively like those of Trochus 

 (Ziziphinus) tiara, Wats., but are flatter, broader, and more umbili- 

 cated. ( Watson.) 



Gulf of Mexico, 287-888 fms. 



T. (Margarita) aeglees Watson, Journ. Linn. Soc, Lond. xiv, p. 

 704, 1879 ; Challenger Gasterop., p. 81, t. 5, f. 10. — Margarita (zgleis 

 Watson, Dall, Bull. M. C. Z. ix, p. 40, 18S1. —Solariella a;gleis 

 Watson, Dall, Bull. M. C. Z. xviii, p. 879, 1889. 



Dr. Dall unites with this species as varieties, the r/w??,a and clavata 

 of Watson. I have no doubt of the correctness of his views. 



Var. RHiNA Watson. PI. 64, figs. 51, 52. 



Shell conical, with a broad and tumid base and a wide narrowed 

 umbilicus ; surface cross-hatched like a file ; when fresh, translucent 

 with a pearly sheen. Sculpture: spirals — there are three to five 

 slightly raised remotely ])eaded threads, of which one lies a little be- 



