468 MOLLUSCA SUB-KINGDOM vi 



Trochalia, Sharpe (Cryptoplocus, Pict. and Camp.), (Fig. 923). Turreted to 



FIG. 9-23. 



FIG. 024. 



Trochalia consobrina, Zitt. A, Nerinea Defrancei, d'Orb. Coral-Rag; Coulanges 8ur Yonne. J>, N. 



Tithonian; Stramberg, dilatata, d'Orb. Coral-Rag; Oyonnax, Ain. C-E, N. Hoheneggeri, Peters. 

 Moravia. Longitudinal section. Tithonian ; Stramberg, Moravia. C, 2/ 3 . D, i/ la E, Longitudinal section. 



pyramidal, usually smooth and imperforate. The inner lip only has a strong, simple 

 fold. Jura and Cretaceous. 



Nerinella, Sharpe (Pseudonerinea, Loriol). Turreted, imperforate. Outer lip and 

 sometimes also the columella with a simple fold. Jura. 



Nerinea, Defr. (Fig. 924). Turreted or pyramidal, usually 

 imperforate. Columella invariably, and inner and outer lips 

 generally, with simple folds. Jura and Cretaceous ; maximum in 

 the Coral Rag (Upper Jura). 



Ptygmatis, Sharpe (Fig. 925). Like the last, except that the 

 folds on both lips and the columella are 

 complicated by secondary constrictions and 

 branchings. Jura and Cretaceous. 



Itieria, Math. (Fig. 926). Elongate-oval, 

 usually umbilicate. Spire short, sometimes 

 insunken. Body whorl very large, more or 

 less enveloping the preceding. Columella 

 and both lips with folds. Jura and Cre- 

 taceous. 



FIG. 925. 



Ptygmatis pscudo- 

 bruntmtana, Gem- 

 mellaro. Tithonian; 

 Imvald, Carpathia. 

 Vertical section. 



FIG. 926. 



Itieria Staszycii, Zeuschner. 

 Tithonian; Inwald and 

 Stramberg. 



Oerithiidae. Menke. 



Family 17. 



Shell turreted ; aperture elongated, oval, 

 or quadrilateral, anteriorly with short canal 

 Outer lip often thickened and reflected, or thin and sharp. Columella sometimes with one 

 or two folds. Operculum horny, spiral. Marine and brackish water. Trias to Recent. 



More than 1000 living, and about 500 fossil species are known, the latter being 

 most numerous in the Eocene. The earliest forms are usually of small size, and have 

 a nearly entire peristome. 



