NERITA. 405 
ghevita albtetila, 
A single illustrative figure having been alone cited by our 
author, and the engraving referred to being that of a shell 
whose features accord with the specified characteristics, the 
determination of the Linnean species was easily effected: the 
more readily so, since the details of the ‘Museum Ulrice’ for 
once agreed with the briefer account of the Nerite in the 
‘Systema.’ Examples of the MNerita albicilla of authors 
(Chemn. Conch. Cab. v. pl. 193, f. 200, a to d) are still pre- 
served in the cabinet of Linneus, and alone of the specimens 
there present answer to the requirements of the combined 
pictorial and descriptive definition. 
Qevita Histrto. 
It is to be regretted that our author did not himself possess 
an example of this species, which has long been involved in 
such obscurity that no writer has dared to positively assert his 
successful recognition of it. Chemnitz having delineated cer- 
tain shells, whose identity with the Linnean Nerite he had 
doubtfully surmised, but which he had not ventured to desig- 
nate with the same appellation, Schréter and Gmelin have 
referred to his figures in illustration of histrio; the former, 
however, has honestly avowed his ignorance of the shell de- 
signed by the illustrious Swede, whose description he has 
copied. Dillwyn has described the Chemnitzian shells for 
his Nerita histrio, but has questioned their identity with the 
species intended by Linneus. Now, as Chemnitz had con- 
founded two very distinct shells (Conch. Cab. v. f. 1948, 9 and 
1960, 1), neither of which, however, precisely harmonised with 
the “labium exterius extus intusque integerrimum”’ of the 
‘Museum Ulrice, Récluz, who has peculiarly devoted rhis 
attention to this group, has bestowed the name Maura upon 
the former (regarded as histrio proper by Deshayes), and of 
Chemnitzvi upon the latter, in the belief that the squamulata of 
Le Guillon (Rev. Zool. 1841) merited the Linnean appellation 
