OF SOUTHERN INDIA. 235 
There are about 70 living species known, chiefly from the tropical seas of 
America, and most of them have been only lately described in the ‘Journal de 
Conchyliologie,’ Being mostly small shells and, when adult, living principally in 
deep waters, they are difficult to procure. Of fossil species about 15 are known from 
tertiary beds, of which several eocene species belong to Strebloceras. We are not 
acquainted with any cretaceous species, although straight fragments of the shells of 
Cacipa may have been occasionally described as Dentaliwn. For it is nearly as 
probable, that fragmentary tubes like ? Dent. rugoswn, Miller (Aach. Petref., 
1851, pt. II, p. 6, pl. 3, fig. 2) belong to Cecum or Fistulana, as to Dentalium. 
I may also mention here the genus Burtinella, which is placed by Mérch in 
the Veruerrps, and will be found treated in that family with greater detail. 
So far as we know Burtinella at the present, it includes chiefly spirally coiled shells 
with tubular whorls, the last of which extends freely, more or less in a straight 
direction. The fossil shells belonging to that genus seem to have been attached 
only in the first stage of age, and were subsequently free; but as they are much more 
strongly built, than the Czcrp# usually are, they were probably litoral inhabitants, 
like most of the Vzruerip# are. Still the characters of the shell of Burtinella agree 
in general far more with Meioceras and Strebloceras of the Czcrpm, than with any 
known Veruetips. We do not know whether the first whorls of Burtinella were 
concamerated, but if they were not, there is scarcely any reason to exclude Buwr- 
tinella, and probably also Tubulostium (n. genus,) from the family Czcrpz. Not being 
in possession of any other materials for examination, than the fossil species from 
South India, so as to test the value of our suppositions, we do not at present make 
any change in the classification. 
XXV. Family, —VERMETID 4. 
H. and A. Adams’ Gen. I, p. 356; Gray, Cat., 1857, p. 126. 
The body of all the Vermzrm is elongated, more or less cylindrical and 
differently twisted, the mantle with the margins entire, embracing the neck; foot 
truncate, cylindrical, club-shaped, not adapted for locomotion, and therefore occa- 
sionally rudimentary; gills enclosed in a cavity on the left side, or near the middle 
of the back; tentacles short, pointed; eyes small, usually at their external basis, often 
on small bulgings ; rostrum produced, teeth, so far as known, placed in seven rows. 
Operculum, if present, spiral and horny. 
The embryonal shell is always spiral and often reverse to that of later growth, 
when the more or less tubular whorls become twisted and coiled in various ways.. 
Regularly coiled shells are to be met with in species, which are, only during the 
embryonic stage of life, attached, and afterwards free. These shells are then 
evidently closely allied to true Caczpz#. In other species, which are fixed during 
their entire life, the coiling and form of the tube itself very much depends upon 
the object, to which they are attached. 
