SUJ-OKDKH 



RHIPIDOGLOS&A 



449 



Family 1). Delphinulidae. 



Shell turbinate or discoitlxl, HxnnUij /////-, nacrwtU /'/</r/f////, //// ornamented 

 .'( nnilly with spines, ribs, or folds. Aperture circular, peristome entire; outer lip" 

 usually expanded or thickened. Operculum horny, often strengthened by a thin calcareous 

 outer layer. Silurian in Recent. 



Graspedostoma, Lindstrom. Globose, narrowly umbilical.-, with .-hurt -pin-, and 

 large transversely striated or cancellated body whorl. Inner liji with an alar process 

 at the end of the columella. Silurian. C. elegantulum, Lind>tr<>m. 



Crossostoma, Morr. and Lye. (Fig. 824). Depressed turbinate, smooth, without 



FIG. 824. 



,'/. 



sp. 

 Ma 



re- 



thru in, d'Orb. 

 .Middle Lias; 

 y, Calvados. 



FIG. 825. 



Liotia Gervillei, 

 IH>sh. sp. Calcaire 

 Grossier ; Haute- 

 ville, near Valogne, 

 France. 



FIG. 826. 



I>ill>liinula segregate, 

 Heb. Desl. Callovian ; 

 Montreuil - Bellay, 

 Maine-et-Loire. 



FIG. 827. 



Delphinula tc< 



Hion-t. sp. Oligocene 



Gaas, near Dax, France. 



umbilicus. Spire short, aperture round, narrowed by a callus. Outer lip somewhat 

 reflexed. Trias and Jura. 



Liotia, Gray (Fig. 825). Depressed turbinate, with transverse swellings. Aperture 

 thickened by a callous rim. Jura to Recent. 



Delphinula, Lam. (Angaria, Bolt.), (Figs. 826, 827). Depressed turbinate, um- 

 bilicate. "Whorls scaly, spinous, or spirally ornamented. Aperture circular, lip 

 without thickening. Trias to Recent. 



Family 10. Trochonematidae. Zittel. 



Shell pyramidal, turbinate, or discoidal, dextral or sinistral, with internal nacreous 

 layer. IVTiorls convex, with one or more longitudinal keels, and sliijlitltj undulating trans- 

 verse striae or ribs. Aperture rounded, sometimes 

 with faint notch. Operculum unknown, presumably 

 horny. Marine. Cambrian to Cretaceous. 



This extinct group is very abundant in the 

 Palaeozoic, and notably so in Jurassic rocks. The 

 shells, as a rule, are highly ornamented, and have 

 been associated by some with the Littorinidae, by 

 others with the Turbinidae or Purpurinidae. They 

 form a distinct family, which is best placed in tl it- 

 neighbourhood of the Turbinidae and Trochidae. 



Trochonema, Salter. Pyramidal to turbinate, 

 deeply umbilicate, longitudinally keeled and trans- 

 versely striated. Aperture round ; the umbilicus 

 surrounded by a keel. Cambrian to Silurian. 



Eunema, Salter (Fig. 828). Pyramidal, with Canada, 

 acute, elongate spire, and no umbilicus. "Whorls 

 with two or more spiral keels, and strong transverse striae, 

 notched anteriorly. Ordovician to Devonian. 



Amberleya, Morr. and Lye. (Eucyclus, Deslongch.), (Fig. 829). Turbinate to 

 VOL. I 2 G 



Fio. 828. 



Eunema strigi- 

 Or- 



Amberleya capitanea, 

 Miinst. Upper Liaa ; 

 La Verpilliere, near 

 Lyons, France. 



Aperture oval, slightly 



