34 CONTRIBUTIONS 
beautifully sculptured by some parasitic animal, so as to 
resemble, in some degree, the net work of a Flustra. It is 
entirely covered with this carved work, and .at the first 
view I thought this made it specifically different. A fur- 
ther examination, however, proved the depredator to have 
no particular preference to species or genera, his workman- 
ship being on many other shelis. 
I am not aware that this genus has been observed in 
the strata of Great Britain. In the admirable tables of 
M. Deshayes, appended to the third volume of Lyell’s 
Principles of Geology, we have six species, five of which 
are found in the Paris basin, the Eocene of Mr Lyell. 
The genus has not, to my knowledge, before been ob- 
served in any of the formations of our country, 
FAMILY MALDANIA. | 
GENUS DENTALIUM.  Linneus. 
D. alternatum. Plate 1. Fig. 2. 
Description. Shell very slightly curved, with about six- 
ieen longitudinal ribs alternating with as many smaller 
ones; near the base furnished with irregular lines of 
growth ; aperture round. 
Length about 1 and 3-4ths inches. 
