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allow of an opinion being formed as to their specific characters ; 
excepting that neither of them seem to accord with any of the species 
particularized by Linnaeus. The remains of a shell belonging to this 
genus is sometimes found among the Devonshire Blackdown fossils. 
XCIII. Mytilus. A longitudinal bivalve, with an acute base ; 
the beaks straight, subacute, and terminal ; the hinge, in most, with- 
out a tooth : only one muscular impression. 
Bruguiere separated from this genus the aviculce and anodontce, 
with such oysters as Linnaeus had included in it ; and Lamarck has 
rendered the genus more precisely determined, by abstracting from 
it also the shells with which he forms his genus Modiola. 
Lamarck describes two species of fossil muscles, M. rimosus and 
M. denticulatus, found at Grignon and Long-Jumeau. Dr. Wood- 
ward mentions several shells of this genus found in different parts 
of England, Catalogue , Part n. p. 62. 
I do not know that I can introduce the following extraordinary 
fossil, Plate XI. Fig. 32, in a more appropriate place than under the 
genus Mytilus, agreeable to the label attached to it, which thus 
describes it : Muscolo petrefatto rappresentante una foglia e di 
ughezzano net Veronese non pi ancora descritto e Jigurato da alcun 
litologo. I have however met, in Catalogi lapidum Veronensium 
mantissa with two figures of this fossil, and the following remarks on 
it: — “ Abunde hi lapides occurunt in Valle vulgo d’ Anguilla agri 
Veronensis, qui etsi aspecto suo, folia demonstrare videantur, nihilo- 
minus minime ad folia ; sed potius ad tegumentum cujusdam piscis 
armati eos pertinere puto, quam tamen opinionem aliorum judicio 
permitto. Egre e multitudine horum lapidum, quadraginta bene 
impressos sejunxi, nam ceteri, qui nuncusque inventi fuere, nullius 
momenti sunt.” P. 11. — The great number of these bodies existing 
in one part, affords a strong argument against either their figures, or 
their markings, having depended on any accidental circumstance : and 
their spathose substance, as well as their thickness, determine them 
