114 MOLLUSCA FROM THE CRAG. 



longitudinal ridges, the centre one the largest ; the extremity produced, straightened, 

 drawn out, and free ; aperture subcircular. 



Diameter of tube, ^ a line. 



Locality. Cor. Crag, Ramsholt and Sutton. 



Red Crag, Sutton, Bromswell, and Brightwell. 



Fragments of this shell are abundant in many localities. One agglomerated mass 

 in my cabinet is almost as large as a hen's egg ; but the specimen figured by Dale, 

 which I imagine to be a group of these tubes, is more than five inches in length, and 

 three and a quarter in thickness. It much resembles V. subcancellatus, Phil. (En. Moll. 

 Sic.), but is not regularly cancellated on the exterior. The tube is ornamented by three 

 lines, in a longitudinal direction, the centre one of which is the most prominent, and 

 forms the base or keel of the volution, so that only two are visible where the shell 

 is regularly spiral, and one upon the base below. The shell, when perfect, is covered 

 with rugae or wrinkles in a transverse direction ; but the terminal portion is smooth, 

 and free. In large masses the volutions are irregular and inconspicuous, though the 

 young shell may frequently be traced by its regularly spiral form. V. subcancettatus 

 is called by M. Philippi solitary; the Crag specimens are generally gregarious. This 

 may, however, be only a variety of that species, as he has suggested. 



Fig. 8 a is a specimen attached to an oyster from the Coralline Crag ; fig. 8 b is a 

 glomerated mass of these shells, from the Red Crag at Bromswell. 



2. VERMETUS BOGNORIENSIS (?). /. Sow. Tab. XII, fig. 9. 



VERMETUS BOGNORIENSIS. J. Sow. Min. Conch, t. 596, fig. 1-3. 



Specimens, of what appears to belong to this species, are occasionally found in the 

 Red Crag. The inner volutions are destroyed in a similar manner to those from 

 Bognor, and the interior of the tube is filled with clay. They are probably washed in 

 from the London clay, and may, perhaps, be the remains of an Annelid. 



C/ECUM,* Mem. 1817. 

 DENTALIUM (spec.) Mont. 

 daECALiUM. Flem. 1822. 

 BROCHUS. Brown, 1827. 



CORNUOIDES. 



ODONTINA. Zborzewsky, 1834, (ex Phil.) 

 ODONTIDIUM. Philippi, 1836. 

 DENTALIOPSIS. Clark, MS. 1847. 



Gen. Char. Shell small, tubular, generally thick and strong ; smooth or annulated ; 

 subcylindrical and arcuated ; open at the anterior extremity, with the margin rounded, 

 sometimes thickened ; closed posteriorly with a rounded or mammillated clausum ; 

 operculum corneous and spiral. 



* Etym. Ccecus, blind, or closed ; taken from cacum, & term used in anatomy. 



