OSTREA. 107 
Linnean cabinet, and alone of its contents agree with the 
original diagnosis. The worst (and probably the first) 
example has only seven distinct rays, the majority have 
eight: the difference of the auricles in magnitude is very 
striking. 
From the details enumerated in the ‘Museum Ulrice,’ more 
especially “auricule subsquales,” which is opposed to the 
“auricula altera minuta”’ of the ‘Systema,’ I can scarcely doubt 
that the Pecten there described was different. 
In the twelfth edition of the ‘Systema,’ “ inequivalvi” was 
erroneously added to the diagnosis, and the numeral 9 re- 
places 7. In the revised copy, the obnoxious “in” has been 
obliterated from “ inequivalvi” and “ plicata, utrinque striata” 
substituted for “sensim undata.” 
It is better, on the whole, in citing the pes-felis of Linnzus 
as a synonym of the Pecten thus designated, to confine the 
reference to the tenth edition, for assuredly the ‘ inzequivalvi” 
of the twelfth edition (though perhaps only a typographical 
error) forbids our referring to that likewise. 
Ostrea pellucens. 
The cited engraving of Argenville is a tolerable representa- 
tion of Pecten varius, and is correctly delineated as having very 
numerous ribs, instead of the nine only allowed it in the 
diagnosis: it is plainly an erroneous citation. Few concho- 
logical writers have hazarded the determination of this Pecten 
(the genus is certain enough); Dillwyn, however, ventured to 
opine that it might be identical with P. ornatus of Lamarck: 
the rough and very numerous raised striz of that shell do 
not, however, correspond to the “radiis novem, levi” of 
the description. 
Linneus did not himself possess an example (as we learn 
from his list) when he originally founded the species: I can 
find nothing in his cabinet, which answer to the details of the 
‘Museum Ulrice.’ The account of the species in that work 
does not ill apply to the Pecten wmbricatus ; the spoon-shaped 
hemispherical scales, however, are more marked in the “ oper- 
