SOLARTTD^. 219 



from Solarium ver}^ desirable. Of many of the palaeozoic Stra- 

 parolli the opercula are known, and they very much resemble 

 those of Torinia, being thick and composed of numerous lamellar 

 volutions. 



[maclurea, Emmons. Shell discoidal, sinistral, flattened 

 above, rounded below ; surface smooth or transversely striated. 

 Probabl}' more nearly related to Bellerophoutidae and Haliotidse, 

 in the vicinitj^ of which it will be more fully described. S. 

 magna, Lesueur (Ixv, 10).] 



SCHIZOSTOMA, Brouu. Shell dextral or sinistral, planorbiform, 

 the whorls flattened or convex; aperture triangular or transverse, 

 the margins sinuous above and below, uniting in a produced 

 point at the periphery. S. Puzosii, Yern. (Ixv, 11). 



COELOCENTRUS, Zittcl. Shell low conical, widely umbilicated, 

 with rounded or angular whorls, having one or two series of 

 tubercles or hollow spines ; aperture round, with entire lip. 

 Devonian to Trias. S. Goldfussi, d'Arch. 



EUOMPHALOPTERTS, Roemer. Shell low conical, widely and 

 deeply umbilicated ; periphery seamed, with fine radial channels. 

 Operculum shelly, concentrically striated and swollen externally, 

 showing spiral whorls internally. S. alatus, His. U. Silurian. 



[raphistoma, Hall. . (Helicotoma, Salter.) Shell lenticular 

 or orbicular, whorls flattened with a carination above ; umbilicus 

 moderate ; outer lip with slight sinus at the keel. S. striatus, 

 Hall. See p. 223.] 



Helicocryptus, d'Orb. 



JDistr. — H.piisillus^ d'Orb. (Ixv, 12\ Corallien. 



Shell depressed orbicular, volutions on the same plane ; the 

 outer one nearly embracing the others, so that it shows a small 

 depressed spire above, and a narrow umbilicus below. 



Stoliczka places this genus near Rotella ; it is perhaps as nearly 

 related to that genus as to the Solariidse. 



Adeorbis, S. Wood. 



Distr. — 10 sp. West Indies, China. Low-water to 60 fms. 

 Fossil, 5 sp. Eur. A. siibcarinatus, Mont. (Ixv, 13). 



Shell depressed orbicular, widely umbilicated ; whorls not 

 numerous, smooth or striate, the last sometimes angular; aper- 

 ture rounded, the outer lip arcuated, simple, sharp. Operculum 

 shelly, subspiral. 



Omalaxis, Desh. 



Distr. — 0. supranitida, Wood (Ixv, 14). 



Shell subdiscoidal, whorls distinctly carinate, peristome not 

 continuous. Operculum elevated, multispiral. 



HoMALOGYRA, Jeffreys. 

 Syn. — Omalogyra, Jeffreys. Ammonicerina, Costa. 



