MYTILUS. 141 
tion of that shell. Moreover, an example of the Lamarckian 
exustus (Kneycl. Méth. Vers, pl. 220, f. 8, 4) is still preserved 
in the Linnean collection, where it is the only specimen there 
present which correctly agrees with the published description. 
Nevertheless, although its presence in the cabinet is asserted 
in the list appended to the tenth edition (not so in the final 
one), I dare not pronounce upon the identity, because the spe- 
cimen agrees still better with the ideal of Mytilus bidens. 
Mérch declares the Linnean exustus to be identical with the 
Mytilus Donungensis of Lamarck and D’Orbigny. I know not 
the grounds of his decision: the colouring scarcely harmonises 
with the “ferrugineus” of the ‘ Museum Ulric.’ 
Mytilus barbatus, 
In the box thus marked in the Linnean cabinet is still pre- 
served the Modiola Gibbsu of Leach (Zool. Miscel. pl. 72, f. 2), 
the Modiola barbata of the ‘ British Mollusca,’ which alone in 
the collection agrees with the definition of the species. Lin- 
neus, in his revised copy of the ‘Systema,’ has added “ Color 
incarnatus; dens nullus,’ which brilliant colouring is natural 
to the shell, when the epidermis, with its serrated bearding, 
has been removed. Both Gualtier and Ginanni exhibit the 
shell described (pl. 2, f. 2), but the barbatus of the ‘ Fauna Sue- 
cica,’ judging from its Northern locality, was in all probability 
a young modiolus. 
Mortilus cdults. 
The Mytilus edulis of authors is marked (Turton, Dith. Br. 
pl. 15, f. 1) for this species in the Linnean collection. In the 
revised copy of the ‘ Systema’ “ cardo fere edentulus” has been 
written, and the reference to Lister, f. 20, corrected by the addi- 
tion of another cypher: references to ‘‘ Penn. Zool. iv. t. 63, 
i073; Knorr}, Cone: 4; t: 75; f, 25” Regenf. .t: 7, £8; “have 
been annexed to the synonymy by the younger Linné. From 
