330 SPECIES OF THE SYSTEMA. 
Since the T.. argyrostomus is a decidedly umbilicated species, it 
cannot be the imperforated Linnean cochlus. Born’s selection, 
then, does not appear unreasonable, for adult examples of 
margaritaceus are almost imperforated. I confess, however, - 
that to me at least the T’wrbo cochlus seems so inadequately 
defined as to be indeterminable. For, although it would not 
be difficult to indicate a species (the 7’. crassus of Wood’s Sup- 
plement to the ‘Index Testaceologicus,’ pl. 6, Tur. f. 43, for 
instance) in which are displayed the few features required by 
the very concise diagnosis, it would be unjustifiable to attempt 
an identification upon such slender grounds of evidence. 
Turbo chrpsostomus. 
The admirable description in the ‘Museum Ulrice,’ and the 
cited figures of Rumphius, Argenville, Klein and Seba (that of 
Gualtier is more doubtful), so evidently pointed to the shell 
which long before the days of Linnsus had borne the equivalent 
appellation of “os aureum,” that its recognition (Turbo chry- 
sostoma, Reeve, Gonch. Icon. vol. iv. Tur. pl. 7, f. 28) has long 
been unquestioned. ‘There are specimens of it in the Linnean 
cabinet, but not in good condition. 
Gruvbo tectum-Persteun. 
The cited figure of Argenville represents a depressed-conical 
sharply-spined T’rochus of the Imperator section, which by no 
means suits the “ovata” “spinis obtusis” of the meagre de- 
scription in the ‘Systema;’ hence the species not having been 
defined in the tenth edition, accordance with the language of 
the ‘Museum Ulrice, not resemblance to the cited engraving, 
must be the criterion of identity. The “faux minime argentea” 
of that publication excludes altogether the idea of a Trochus, 
since all the true members of that vast genus exhibit a nacreous 
aperture. Born’s recognition was, therefore, inaccurate: his 
figure, moreover, bears no resemblance to that of Argenville. 
33 66 
