23 



It has been before remarked that, it was the intention of 

 Doctor Solander, had he lived, to have formed a new ge- 

 nus of this family offhells, which have been divided amongfi; 

 the Mya and Macta genera, without being, in fa6l, connected 

 with either, according to the fyllem of arrangement by the 

 flru(51ure of the hinge, 



Petiver has aptly denominated one of the fyeciesfpoon- 

 hinge, from the circumflance of the tooth being concave, 

 fomewhat refembling the bowl of a fpoon. Upon a former 

 occafion we did not think it neceflary to make a new genus, 

 for the few Bntijlj fliells then confidered as properly be- 

 longing to this family, but as a more minute inveftigation of 

 the flru(^ture of hinges, together with additional difcoveries, 

 have convinced us of the impropriety of claffing feveral 

 fpecies with other genera, which ought to be brought toge- 

 ther as dilHn6l from all, we have thought proper to cla(s 

 them by themfelves, and to place this new genus next to 

 Mya. Having fo done we beg that the following ihells, ac- 

 cording to our former arrangement, may be brought into this 

 genus. Myaprcetenuis, pubefceyis, di/iorta ; Mactra compuffa 

 tenuh, and Boyfii; to which we have to add the annexed 

 new and interefting fpecies. 



Shell oblong, flat, thin, glolly, white, confiderably attc- Prismatica ^< 

 nuated at one end, and obfoletely ftriated concentrically ; x^b, 26" f. 3. 

 the umbo very fmall, placed neureft to, and turning towards 



the 



