ARCA. 93 
Area pella, 
The words of the ‘Systema’ leave no doubt as to the modern 
genus (Nucula, section Leda) in which the Arca pella should 
be located, and the authenticated Mediterranean locality com- 
bined with the expression “ oblique striata” so limits our 
selection, that the conclusion, as suggested by Philippi, of its 
identity with the Sicilian N. fabula (Sow. Conch. Il. Nuc. f. 13) 
is almost inevitably arrived at. No shell in the Linnean 
cabinet exhibits the characteristics required for identification. 
In the earlier edition the words “ut testa fere rostrata, dis- 
tincta utrinque fossula” intervene between “ prominens” and 
“transverse striata.” 
Area lactea, 
Despite the brevity of its description, and the absence of 
any auxiliary synonym, the Arca lactea has long been recog - 
nised by conchologists in the native species which bears that 
name in modern works (Brit. Moll. pl. 46, f. 1, 2, 3). Some 
bald bleached valves of that widely diffused European bivalve 
are present (as indicated) in the Linnean cabinet, and alone 
of the shells therein contained answer the requirements of the 
definition. 
The authenticated locality could alone have enabled natu- 
ralists to determine the species. 
Arca antiquata. 
The presence of a marked example, which agrees with its 
description, and still reposes in its marked receptacle in the 
Linnean cabinet, enables us to ascertain what species of Ark 
was regarded by our author as entitled to this designation. 
The type (which is recorded as possessed by our author from 
the first) reminds us strongly of Lister’s ‘ Hist. Conch.’ pl. 330, 
