MYTILUS. 145 
tion of the species. No other member of the same genus, the 
preceding excepted, of which, indeed, comp/anata is regarded as 
a mere variety by that indefatigable student of the Naiades, the 
American Lea, is to be found in the collection. The referred 
to engravings were doubtlessly selected as the nearest represen- 
tations extant; all three, however, are designed for different 
species. Gualtier’s figure represents a Unio, Lister’s f. 2 an 
ordinary example of the Anodonta cygnea, f. 9 a Virginian 
Anodonta. The species intended we know to have been Eu- 
ropean, from its occurrence in the ‘Fauna Suecica: and the 
dentition of Unio forbids our regarding Gualtier’s shell as illus- 
trative. Had the winged variety of cygnea, ordinarily termed 
A. anatina, been designed by our author, he would scarcely 
have written in his own copy “similis 28 (Unio pictorum) sed 
absque cardine.” 
Mytilus vivtdis. 
The Mytilus smaragdinus (Chemn. Conch. Cab. vol. vii. pl. 
84, f. 746) of authors (including opalus) is the species pre- 
served in the box thus marked in the Linnean cabinet. Lin- 
neus originally described the species from a very young speci- 
men: subsequently to his publication he appears to have met 
with more mature examples, for in his revised copy he has 
written ‘‘ oblonga, antice compressa, sublunata,” &c. 
Mivtilus vwubdber. 
This shell originally appeared in the tenth edition of the 
‘Systema’ with less than two lines of description, and a queried 
reference to Argenville’s drawing of a young Mytilus Afer, a 
smooth brown-marbled mussel whose characters are in accord- 
ance with those demanded by the definition. The same words 
are repeated in the twelfth edition, save that “‘ postice” has 
been replaced by “antice,’ and a reference to the ‘Museum 
Ulrice’ has been added. In the Vienna reprint, the note of 
interrogation after the citation of Argenville has been erro- 
neously omitted. 
U 
