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, ete. C. macrostoma, Hinds (1xix, 52). 
CERITHIELLA, Verrill, 1882. (Lovenella, Sars.) Shell subulate; 
whorls numerous, cancellated ; aperture terminating in a short, 
distinct reflected canal. Norway, New England. C. metila, 
Loven (lxix, 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. C. reticulatum, Da Costa (Ixix, 54). 
CERITHIOPSIS, Forbes and Hanley. Shell like Bittium; nuclear 
whorls sinistral. Opereulum pointed, nucleus apical. Proboscis 
retractile. Northern. OC. rugulosus, Ads. (1xix, 55). 
SEILA, A. Ad. Shell like Cerithiopsis, transversely lirate. 
CERITHINELLA, Gemm. Turreted to cylindrical, not perforated ; 
mouth quadrangular, with very short canal; growth-lines re- 
curved under the sutures. C. J/talica,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. C. rostellaria, Buv. Jurassic. 
vicaRIiA, 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. C. Verneuili, d’Arch. Eocene; Hast Indies. 
FIBULA, Piette, 1857. 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. /. 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, 
CERITELLA, Morris and Lycett, 1850. (Costellifer, Meek. 
Tubifer, Piette.) Shell small, resembling Actzeonina 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. 
