ISO 



This was taken at Plymouth by the trawl net, and is 

 rather larger than that before defcribed. 



OSTPxEA. 



;SrRiATA. I"^ making this fliell of Lister an oyftcr, we had fol- 



p. ]53. lowed our precurfors, but not without doubt; for though 



we had never feen the flat, or what had been termed the 

 upper valve, there always appealed fufficicnt charafter 

 in the hinge of the convex valve, to have placed it with 

 the Anonuce, had not Lister, Da Costa, and others, 

 fpoken of it as an 0\Jler, with fo much confidence. It 

 is, however, beyond difpute, an Anomia, and we think, 

 there is fo little doubt with refpeft to the A. undulata 

 being only the young of it, that the synonyma of thefe 

 two fliells, fliould be brought together under the title of 

 the latter. 



It is now eafih'^ accountable, why fo many concave, 

 or. as was termed, the under valves, were found in pro- 

 portion to the upper or flat valve; for, as Da Costa 

 fays, there are hundreds of the former found to one of 

 the latter. The faft is, that the fl,riated, or concave 

 valve, is the upper, and the flat, or perforated valve 

 adheres fo firmly to the rocks, as not often to be fepa- 

 rated with the other; and therefore the perfeft fliell is 

 never met with but alive, adhering to other fubflances : 



indeed, 



