as well a as all t 
Soh W\iefi Anomice feud in. Detbypoires 1 5 cag 
beak of the larger valve. \It isnot ‘however conftantly placed ‘in 
that fituation, as.one of the recent ‘fubjeéts, the Auomia Ephippium, 
Lin. Syf. p. 1150, and the foffil deferibed, in, the preceding Pages, 
evince. Nor does it appear that it fhould be confidered as a prin- 
cipal or ‘determinate charaéteriftic of this family ; for in examining 
fome hundred fj ecimens, fimilar to thofe reprefented by fig. 7, 8, Io, 
He different {pecies which come under the divifions 
thofe figures elucidate, I have not been‘able to detea the {malleft 
aperture in either of ‘the valves, though many of the {pecimens 
were far more perfect than fome of thofe in which the perforation 
“is wilde fufficiently vifible, . I am well aware that fome of thefe 
imperforate Anomia would be ranked by. Conchologitfts, who efteem 
the aperture as the leading charaéter, under another genus; for in- 
ftance, the Anomia Gryphus, and other {pecies of a like form, with 
the Ofree. But though there may be fome doubt refpecting the 
family to which the foffils in queftion properly belong, certainly 
there is no genus yet eftablifhed;* except Anomia, that''y Will ‘receive 
thofe Tot bivalves reprefented by fig. 7, 8, ‘10---Muft-we 
therefore form a new genus forthe’ 'fabje&ts mnder confideration, or 
adhere tothe definition of an Anomia Linnzus has left us, in which 
the perforation i is not, I' think, confidered as a conftant generic 
_ charaéter? Perhaps till more accurateinveftigations piiove the hinge 
(from which without doubt the leading charaéter?in:every-family of 
bivalves fhould'be taken) in the perforated Anomia, to differ from 
that of the’ ‘imperforate, it will be advifable for thofe tvho are en- 
gaged in the purfuit of extraneous foffils to confider al/ bivalves with 
unequal valves, the beak of one being produced ar more prominent than that 
of the other ¢, generally the fmaller valve), and for the moft part curved 
over the he bie as Jpelonging to the genus of Anomia, 
Von, IV. H An 
