TROCHUS. 317 
where rightly quoted by him for 7. tuber. The traditional 
identification was probably established from Argenville’s figure 
having been fortunately selected as the typical one; an idea 
founded upon the name “la Sorciere,” Latinised by magus, 
attached to it (not always a safe method of proceeding). The 
Mediterranean locality, and details of the ‘Museum Ulrice,’ 
where an ash-coloured variety seems to have been described 
from, contributed, it is probable, to this decision. 
Trochus niwodulus, 
As fishes, not shells, are delineated in the thirty-fourth plate 
of Seba’s folio, it is manifest that the faulty reference was a 
typographical error. Linnzus did not himself possess this 
species, which, owing to the very peculiar combination of its 
recorded features, has been generally recognised in the Mono- 
donta thus named by Lamarck (T’r. lenticularis, Chemn. Conch. 
Cab. vol. v. pl. 171, f. 1665). 
Trochus muricatus, 
Deshayes has confessed his inability to recognise this species 
from the meagre account of it in the ‘Museum,’ nor has any 
other naturalist been more successful. For the cited figure of 
Gualtier (the only pictorial reference), a very rude drawing, 
with somewhat the aspect of Littorina muricata, does not 
display the slightest vestige of an umbilicus, as required. It 
is highly probable that the Linnean shell belonged to that 
genus, but neither the manuscripts nor the cabinet of our 
author (who did not possess an example of it) throw any addi- 
tional light upon the subject. One might have hoped from the 
limiting locality, that Philippi, who has so ably investigated the 
Testacea of the Mediterranean, could have found some species 
there to which the few recorded characteristics would exclu- 
sively apply; but experience has taught me that little con- 
fidence can be reposed in the unauthenticated habitats of our 
author. 
