398 SPECIES OF THE SYSTEMA. 
Perita radula. 
The Neritopsis cancellata of Sowerby’s ‘Genera of Shells’ 
(f. 1) is marked for this species in the Linnean collection, and 
well agrees with the more detailed features mentioned in the 
‘Museum Ulrice.’ 
Alevita corned, 
Born alone, among the older writers, appears to have ob- 
served any shell which answered to the characters of this 
species; his account of it has been translated by Dillwyn in his 
‘Descriptive Catalogue.’ Récluz, whose comprehensive ex- 
amination of the Nerite group entitles him to a high rank as an 
authority respecting them, has adopted the identification by 
Born, and recognised the Linnean shell as inclusive of the four 
following varieties: Neritina amphibia and ampullaria of Lesson 
(Voyage Coquille, yol. 1. pl. 16, f. 1, and p. 376), N. subsulcata 
of Sowerby (Conch. IIl.), and N. fasciata of Lamarck (Encyel. 
Méth. Vers, pl. 455, f. 5). He has excluded the synonym of 
Argenville, and considered the cornea of Forskal to be essen- 
tially distinct. ‘There is much plausibility in this conclusion, 
although the colouring specified in the ‘Museum’ is not 
habitual to the supposed representative, and the expression 
“plurimis” is too strong for the spiral strie: nevertheless, it 
would be difficult to point out any edentulous Neritina (and 
“labiis edentulis” is a most important feature) that in the 
main agrees so well, and, whatever Argenville’s figure may have 
been designed for, so nearly resembles it (Sow. Thes. Conch. 
Neritina, f. 71) in size and painting. This engraving, however, 
was a dorsal view of a true Nerita (chameleon ? ?), but was the 
nearest approach then extant to the Neritina cornea of Récluz’s 
Monograph. I find no shell in the Linnean collection that 
corresponds with the description in the ‘Museum Ulrice,’ or 
even with the brief diagnosis of the ‘Systema,’ as illustrated by 
the figure of Argenville. 
