HELIX. 389 
this species, the writers upon English Testacea have unani- 
mously selected the Bulla velutina of Miller (Zool. Dan. i. 
pl. 101, f. 1 to 4) as its representative. The worn fry of that 
shell may approach in some respects the requirements of the 
diagnosis; but “ apertura postice elongata” cannot be affirmed 
with truth of the adult. No specimen of it is present in the 
Linnean cabinet, where the nearest approach (and I suspect 
the real representative of it) is the Lacuna pallidula (Brit. Moll.), 
of which the imperforated variety patula exactly answers to the 
description. It is not, however, desirable to effect any altera- 
tion in the names; for the species of the ‘Systema’ was too 
imperfectly constituted to claim precedence: the definition 
would apply almost equally well to many other shells. More- 
over, as the name-Velutina is now universally accepted in a 
generic sense, the specific epithet levigata may fairly be re- 
tained, inasmuch as the shell has been clearly defined by our 
British writers under that appellation, and may possibly have 
been the species so denominated by the illustrious Swede. 
Helix Balthica. 
Our author did not possess this species, which, although 
described somewhat more fully in the ‘ Fauna Suecica,’ does 
not appear to have been identified by the older conchologists 
(Miller, Chemnitz, Schréter, Gmelin, Dillwyn, &c.). 
Nilsson, in his very accurate account of the land and fresh- 
water mollusks indigenous to Sweden (Hist. Moll. Suecie Ter. 
et F'luy. p. 65), has recognised it in his Limn. Balthicus, which is 
stated to be found on sea-weed in brackish water (a remarkable 
habitat for a member of the genus Limnea); and this identifi- 
cation is supported by Menke in the ‘ Zeitschrift fiir Malako- 
zoologie’ for the year 1845. ‘The ‘ad maris Balthici littora” 
fayours the surmise; and assuredly, in relation to a Swedish 
shell, the opinion of one who has peculiarly devoted his atten- 
tion to the Testacea of that region, and who is ordinarily so 
correct in his views, is not undeserving of our respect. 
