Pir 
E + 
Fx 
336 Marine Shells of Massachusetts. 
nine or ten whorls, and is-but a quarter of an inch 
g; but our species has sixteen whorls, and is six 
sof an inch in length. Montagu remarks in his 
Supplement, that, as an invariable character, the M. 
tubercularis has three series of tubercles of equal size 
on each .volution. 'Turton’s description coincides 
with this remark. But, in the C. E'mersonii, the 
middle series does not appear at all until after- ten 
volutions (the whole number in the English shell), 
and is always much less than the outer two. 
Since this species was deseribed, it has been found 
in a bed of mud in the harbour of New Bedford. 
None of these individuals were in a fresh condition, 
and the majority of them had lost most of their color 
and. gelatine. Six-tenths of an inch is a common 
length. Mr. Shiverick has found, in New Bedford 
and Dartmouth, a few specimens, one of which is .8 
inch in length, and .17 inch in breadth.* 
Cerithium nigrocinctum. Nob. Journ. of this 
Soc., Vol. II. p. 286. Since this species was describ- 
ed, it has been found in the harbour of New Bedford, 
and in a cove on the east side of Fairhaven. It 
should be remarked, that the color of the black sutu- 
ral ridge is much more obvious, when exposure after 
the death of the animal has rendered mie other parts 
cinereous. 
Cerithium Greenii. Nob. Journ. of this Soc., Vol. 
* Dr. Jay, in the third edition of his Catalogue, mentions Minn 
chusetts Bay as its habitat, but this is probably an nétror. I am not 
aware that it has yet been found out of the harbour of New Bedford. 
The reference to Adans., as the original describer, is obviously an er- 
ror of the printer. 
