OF SOUTHERN INDIA. 167 
imperfect, and no columellar plaits are referred to either in the figure or in the sin- 
cular description of the author. The locality and geological position are equally 
unknown; and most probably will remain so unless somebody else rediscovers the 
fossil and settles these points. 
Localities—Alundanapooram. and Ni innyoor in Trichinopoly; at the former 
locality, which belongs to the Trichinopoly group, the species is not rare, but at the 
other locality only a single specimen has as yet been found. It is a small specimen 
and also somewhat slender, but it certainly does not belong to Lyria formosa (p. 97), 
which at the last locality in the same white limestone is pretty common. The 
ribs are not intersected near the suture by spiral sulcations, as they are in that 
species of Lyria. 
Formation.—Trichinopoly and Arrialoor groups. 
XVII. Family—THEREBRID. 
(Vide H. and A. Adams’ Genera I, p. 223; Acvsrpz and Pustonrrrap”, Gray, Guide, 1857, pp. 
and 22; Zrrrsripz and Pusroverzr1pz, Chenu’s Manual, I, pp. 218 and 221). 
The animals of the Tzrrzripz have a small foot, the mantle enclosed, and 
the siphon more or less prolonged. ‘The proboscis is occasionally strong, thick, 
and entirely retractile, sometimes, however, very short or even rudimentary. The 
teeth, so far as known from a few species, resemble those of Conus: they are 
subulate, elongate, and arranged in two series; in other species, however, no teeth 
have been discovered at all. The same is the case with the tentacles, which when 
present or at least externally traceable, are short, thick at the base, and close together 
on the side of the mouth or proboscis. The eyes are externally near the end of: the 
tentacles, or within their length, or néar the basis; sometimes they are said to 
be wanting. 
The operculum is horny, ovate, and lamellar. The turreted shells are always 
distinguished by their solid structure, more or less polished surface, and a large 
number of volutions. The mouth is either abrupt with a notch in front, or extended 
into a canal of moderate length; the outer lip is sharpened, not thickened exteriorly ; 
the columella often more or less twisted, sometimes with one or two distinct folds, 
placed in a manner similar to those in several Crriraip2. 
Hornes gave, in his Mollusca of the Vienna basin (Abhandlungen Geol. Reichs- 
Anst. Wien, Vol. III, p. 125), afew practical hints how to distinguish imperfect 
specimens of Zerebra from Twurritella, Cerithium and others, but it is not clear in 
what way he thinks a sub-division of Zerebra practicable according to the differences 
in the spiral angle (vide ibid, p. 127). 
H. and A. Adams propose to divide the family Tzrrerrpx into two sub-families, 
PUSIONELLINZ and rereBrin®. The former is subsequently (Genera, II, p. 656) 
referred to the Buccryip2. 
The pusronettin2 (PustonetLapms, Gray; PustonrLLip®, Chenu) are repre- 
sented by one genus only, Pusionella. They are turreted or ovately elongated 
poreellanous shells, with smooth polished surface, a tolerably produced anterior 
