470 



MOLLUSGA 



SUB-KINGDOM VI 



emargination or faint canal. Inhabits only brackish water or estuaries. Cretaceous 

 to Recent. 



Sub-genera : Tympanotomus, Adams (Fig. 934) ; Pyrazus, Telescopium, Montf. ; Cerithidea, 

 Swains. ; Lampania (Fig. 935) ; Pyrenella, Gray ; Sandbergia, Bosq. 



Family 18. Aporrhaidae. Philippi. 



Shell fusiform, turreted, or conical ovate. Aperture produced anteriorly in a canal. 

 Outer lip expanded in a wing-like or digitiform fashion, or thickened. Operculum horny. 

 Marine. Jura to Recent ; maximum in Jura and Cretaceous. 



Alaria, Morris and Lye. (Figs. 936-938). Shell turreted; aperture 

 with long or short canal. Outer 

 lip not overriding the last whorl, 

 digitated or winged. Spire and 



FIG. !)3(3. 

 Alaria myurus, Deslongch. 

 Lower Oolite ; Bayeux, 

 Calvados. 



FIG. 937. 



Alaria arniata, Morris 

 and Lye. Great Oolite ; 

 Minchinhampton, Eng- 

 land. 



FKI. 



FIG. 938. 



Alaria (Anchura) cari- 

 nata, Mant. Gault ; 

 Folkestone, England. 



body whorl often retaining traces of apertures at earlier stages. 

 Jura and Cretaceous. 



Sub -genera: Dicroloma, Gabb ; Anchura, Conrad 

 (Fig. 938). Jura and Cretaceous. Diempterus, Piette. 

 Jura. 



Spinigera, d'Orb. (Fig. 939). Whorls keeled 

 and ornamented with two opposite rows of spines. 

 Jura. 



Aporrhais, da Costa (Chenopus, Phil.), (Figs. 

 940-942). Like Alaria, but margins of aperture 

 elongated posteriorly in a canal, which remains 



Spinigera semicari- 

 nata, Goldf. sp. Callo- 

 vian ; Montreuil-Bellay, 

 Maine-et-Loire. 



Very abundant in 



FIG. 040. 



Aporrhais (Dimor- 

 i) calcarata, 



owb. Upper 

 nd ; Black- 



FIG. 942. 



Aporrhais (Lispodestlies) Reussi, Geinitz var. 



Aporrhais tridttctylus, A. Braun. Oligo- Greensand ; Black- megaloptera, Reuss. Planer; Postelberg, 

 cene ; Hackenheim, near Creuznach. down, England. Bohemia. 



either attached to the spire, or extends free from the same. Outer lip expanded, 

 digitated, or lobed. Jura to Recent. 



