434 SPECIES OF THE SYSTEMA. 
that the nimbosa of the ‘Museum Ulvice’ was distinct from the 
specimen described in the earlier publication; assuredly the 
“cavitas alba” does not suit the green interior of the ac- 
cepted representative. Although even the limited synonymy 
of that work, in which Argenville, f. C, was first substituted 
for the previous I, includes several dissimilar species, none 
of the drawings exhibit the nodose ribs alluded to in the 
description. 
Patella nwudecula, 
Chemnitz, Schréter, Gmelin, and most of the earlier con- 
chologists, did not succeed in recognising this shell, which was 
not adequately illustrated by either synonym or description. 
Dillwyn, an enlightened follower of the Linnean arrangement, 
has considered it identical with the P. rosea of Gmelin, a species 
constituted almost entirely from a shell represented by Martini 
(it 0)': 
The Mediterranean Fissurella (Humph. and Da Cost. Conch. 
pl. 7, f. 16), termed rosea by Philippi, and suspected by him to 
be the true nubecula, is precisely identical with some specimens 
(plate 4, f. 10) in the Linnean collection, which analysis demon- 
strates (for they exclusively agree with the definition, and our 
author has declared his possession of examples) to have been 
the original types of this Patella. 'The stated habitat, more- 
over, 1s in perfect accordance with the true locality, and no 
other Fissurella from that region is known to exhibit the speci- 
fied painting: the coloured ring that encircles the perforation 
internally becomes obsolete in adult examples. Plate 529 of 
Lister’s ‘ Historiz’ has been referred to in the revised ‘Systema,’ 
a figure which, although not an accurate delineation of the 
object intended, displays the nearest approach to its general 
aspect of the engravings extant at that period. 
