248 CERITHIID^. 



and the sculpture usually becomes obsolete on the last whorl. 

 The few species inhabit deep water, sandy bottom, at the Philip- 

 pines, China, etc. G. macro stoma, Hinds (Ixix, 52). 



CERiTHiELLA, Verrill, 1882. (Lovenella, Sars.) Shell subulate; 

 whorls numerous, cancellated ; aperture terminating in a short, 

 distinct reflected canal. N'orway, New England. C. mefula, 

 Loven (Ixix, 53). 



BiTTiUM, Leach. (Cerithiolum, Tiberi. Platygyra, Morch.) 

 Shell elevated, with numerous granular whorls, and irregular 

 varices ; anterior canal short, not recurved ; inner lip simple ; 

 outer lip not reflected, usually with an exterior rib. Operculum 

 four-whorled. Animal : Operculigerous lobe with rudimentary 

 expansions on the sides and furnished with a roundish, lanceo- 

 late cirrus. Numerous small northern species, low-water to 80 

 fathoms. G. reticulatum, Da Costa (Ixix, 54). 



CERiTHioPSis, Forbes and Hanley. Shell like Bittium ; nuclear 

 whorls sinistral. Operculum pointed, nucleus apical. Proboscis 

 retractile. Northern. C. rugidosus. Ads. (Ixix, 55). 



SEiLA, A. Ad. Shell like Cerithiopsis, transversely lirate. 



CERiTHiNELLA, Grcmm. Turretcd to cylindrical, not perforated ; 

 mouth quadrangular, with very short canal ; growth-lines re- 

 curved under the sutures. G. ItaMca, Gemm. Jurassic. 



DiTRETUS, Piette, 1874. Turreted ; mouth oval or rounded, 

 with very short, entirely rounded canal ; inner lip spread out, 

 callous ; outer lip thickened ; whorls with longitudinal rows of 

 tubercles. G. rostellaria, Buv. Jurassic. 



viCARiA, d'Arch, 1854. Turreted; whorls spirally striated, 

 with a row of tubercles below the suture ; canal short, recurved ; 

 inner lip callously thickened ; outer lip with a deep, broad, 

 superior sinus, G. Ver^ieuili, d^ Arch. Eocene; East Indies. 



FIBULA, Piette, 1851. Shell elongated, columella straight, with 

 a rudimentary groove near the base ; outer lip arched, slightly 

 notched at the suture ; base of the aperture forming a slight 

 canal, or rounded and entire, depending upon the exact period 

 of growth at which the animal perished.. The species of this 

 genus possess characters intermediate and approximating them 

 to Turritella and to Cerithium. Fossil, 21 sp. Jurassic to 

 Cretaceous ; Europe, India. F. undulosa, Piette (Ixix, 56). 



EUSTOMA, Piette, 1855. Shell in the young state resembling 

 Cerithium ; in the adult the margins of the aperture are much 

 expanded and posteriorly united by an indistinct canal ; canal 

 elongated. Several species. Great Oolite ; Ardennes. 



CERiTBLLA, Morris and Lycett, 1850. (Costellifer, Meek. 

 Tubifer, Piette.) Shell small, resembling Actseonina in form, 

 the last volution being somewhat ventricose and largest, but 

 terminating anteriorly with a short and slightly twisted canal. 

 C acuta^ Morris and Lycett (Ixix, 57). Jurassic. 



