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, without a 

 tooth : only one muscular impression. 



Bruguiere separated from this genus the avicute and anodontte, 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. dentiadatus, found at Grignon and Long-Jumeau. Dr. Woodward 

 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 XL 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 rappresmtante unafoglia e di ughezzano net Veronese non pi 

 ancora descritto efigurato da alcun litologo. I have however met, in Cata- 

 logi lapidum Veronensium mantissa, with two figures of this fossil, and 

 the following remarks on it: " Abunde hi lapides occurrunt in Valle 

 vulgo tfAnguilla agri Veronensis, qui etsi aspecto suo, folia demonstrare 

 videantur, nihilominus minime ad folia; sed potius ad tegumentum 

 cujusdam piscis armati eos pertinere puto, quam tamen opinionem 

 aliorum judicio pennitto. Egre e multitudine horuin lapidum, quadra- 

 ginta bene impressos sejunxi, nam ceteri, qui nuncusque inventi fuere, 

 nullius momenti sunt" P. 11. The great number of these bodies exist- 

 ing 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 not 



