458 MOLLUSCA SUB-KINGDOM VI 
Callonema, Hall (Isonema, Meek and Worth). Turreted, oval to globose ; whorls 
covered with lamellate transverse ribs; aperture circular. Silurian and Devonian. 
Scoliostoma, Braun. Devonian. Chilocyclus, Bronn (Cochlearia, 
Braun). Trias. 
Scalarta, Lam. (Scala, Klein ; Ctirsotrema, Morch.), (Fig. 872). 
Turreted ; whorls strongly arched, with transverse ribs, and often 
also spirally striated. Aperture round, outer lip sometimes thickened. 
Trias to Recent. 
Family 2. Solariidae. Chenu. 
Shell depressed conical, deeply and broadly wmbilicate, without 
nacreous layer. Whorls angular; operculum horny or caleareous, 
spiral. Embryonal spire 

heterostrophic. Marine. 
Fic. 872. Cretaceous to Recent. 
Scalaria lamellosa, The Solaritdae ex- 
Brocchi. Miocene ; off 
Baden, near Vienna. hibit some resemblance to 
the Huomphalidae, from 
which they are distinguished principally 
by the heterostrophic nucleus. 

Fig. 873. Fic. 874. 
Gi Me : mn At 5 iz 
Solarium, Lam. (Figs. 873, 874). goariwm simplex, Solarium Leymeriei, Ryckholt. 
Aperture quadrilateral; operculum horny; Bronn. Miocene; Tourtia (Upper Cretaceous); 
: Niederleis, Moravia. Tournay, Belgium. 
umbilical angle notched or sharp. Jura 
to Recent. A number of Mesozoic forms confused with this genus probably belong to 
Ewomphalus. 
Torinia, Gray. Tertiary and Recent. Bifrontia, Desh. (Omalaxis, Desh.). Eocene. 
Superfamily 3. TAENIOGLOSSA. Bouvier. 
Teeth of the radula seven in each transverse row. Mainly holostomate forms, but 
some genera have deeply notched apertures, as in the higher divisions. 
Family 1. Purpurinidae. Zittel. 
Thick-shelled, oval, with platform-like spire, and without 
pearly layer. Whorls flattened beneath the suture and 
angular, the angles often beset with nodes. Body whorl 
large ; aperture oval, with anterior emargination, and 
discontinuous peristome.  Operculum unknown.  Ordo- 
vician to Cretaceous. 
Scalites, Conrad. Spire short and acuminate ; whorls 
flattened superiorly and bounded by a sharp angle at the 
suture. Body whorl very large, smooth ; aperture faintly 
notched. Ordovician (Chazy) ; according to Laube, also 
Triassic. 
Fra. 875. Trachydomia, Meek and Worth (Trachynerita, Kittl) ; 
Purpuroidea nodulata, Young ana Pseudoscalites, Kitt]; Tretospira, Koken. Trias. Brach- 
Hates prlcory oy pale Minchin- trema, Morris and Lye. ; Tomocheilus, Gemm. Jura. 
aa Purpurina, VOrb. Elongate-oval. Whorls angular 
superiorly, spirally ribbed, with transverse folds or costae, highly ornamented, often 
with umbilical fissure. Aperture oval, anteriorly notched. Rhaetic and Jura. 
Purpuroidea, Lycett (Fig. 875). Spire with successive steps or platforms, the 

