162 
SHELLS. 
NATICA INTRICATA. Natica intricala, Fleming’s 
Brit., An., p. 319. Natica intricata, Donovan’s Br. Sb.> 
t. clxvii. Natica canrena, Montagu’s Test. Brit., Sup. 148. 
The only British Naturalist to whom I am able to refer, 
for information concerning the Natica intricala, is Dr. Flem- 
ing, who in his History of British Animals gives the 
authority of Donovan’s British Shells, under the name above 
given, and to Colonal Montagu, who terms it N. canrena ; but 
he adds, “this species has occurred only to Mr. Donovan." 
And when I add, that Professor E. Forbes (Malacologia 
monensis, p. G2) supposes it to be the same with N. nilida, 
and that it is not to he distinguished from some other foreign 
species, it will be allowed to be of rare occurrence; and I 
am therefore led to hope that a description of it, derived 
from more than one example, and compared with the kindred 
species N. glaucina of about equal size, and both of these 
with several smaller specimens of each, will be found 
interesting. 
The shell termed by Fleming N. intricata has too rarely 
come within the observation of British Naturalists to have 
received so many names, as the fancies or mistakes of authors 
have affixed to the more common species. But to avoid all 
errors in reference it is necessary to say, that under the 
name A atica glaucina is meant that which by Pennant is 
denominated Nerita glaucina, and it is believed, also by 
Montagu : by Fleming Aot/ca glaucina. Professor Edward 
Forbes, as quoted above, terms it Eatica monilijera , from 
a supposition that it may be the shell so called by JLamark; 
and the same is adopted by Macgillivray : (Molluscous 
Animals of Aberdeen &c., p. 128.) 
In September of the present year (1844) I obtained a 
specimen of Natica intricata, from Penzance, and this I 
supposed to be the first I had ever seen. But in the course 
ot the same month 1 obtained a much larger specimen front 
Plymouth sound; and a comparison of this pair with a fine 
specimen of the more common N. glaucina will enable me to 
give a measurement and description which will in some 
measure fix the identity of the rarer species. 
The smaller specimen of N. intricata here referred to, 
measured ten twelfths of an inchin its longest diameter; 
but the larger, which was seventeen twelfths in its longest 
diameter and thirteen twellths in its shortest diameter, 
afforded a closer comparison with N. glaucina ; my largest 
specimen of which is sixteen by thirteen twellths in these 
diameters. The latter, therefore is a rounder and more 
compact shell, the greater comparative length of N. intricate * 
being obvious on inspection. They differ also in the ar- 
