90 
considered as a Haliotis, but which certainly belongs to the following 
genus, which differs from Haliotis, in being without holes. 
LXV. Sigaretus. A depressed oval, nearly auriform, shell, with 
a short spiral columella : the opening entire, very wide, spread out 
towards the summit of the right lip, and longer than wide. 
The shell, for the reception of which Lamarck formed this genus, 
is the Venus’s ear; Sigaretus, of Adanson ; Helix haliotidea, of 
Linnaeus ; and Bulla velutina, of Muller. This is an exceedingly 
rare fossil. The only specimen which I have seen is one which I ob- 
tained at the sale of the Museum of Mr. Strange ; and which, I after- 
wards discovered, by the purchase of some of Mr. Strange’s manu- 
scripts, had been thought of sufficient consequence to be the subject 
of a plate engraved by Antonio Gregori, from a drawing of Gaspero 
Massini. This is a Tuscan fossil. 
A fossil shell of this genus, but apparently not of this species, is 
found in St. Peter’s Mountain, Maestricht, and is figured by Faujas 
St. Fond, Hist. Nat. de la Montague de St. Pierre, p. 166, Plate 
XXVIII. Fig. 3. 
Plate VI. Fig. 9, is a magnified representation of a shell of this 
genus, which is shown of its natural size, Fig. 10. This microscopic 
fossil was found in the calcareous sand contained in the cavity of a 
gigantic cerithites. 
LX VI. Argonauta. A very thin involuted boat-like univalve ; the 
spire turning into the opening ; with a double, tubercular keel. 
I have no knowledge of any shells of this genus having been found 
in a mineralized state. 
