is ; another name, according to Swainson, was given by Dr. 

 Turton ; and a third, that of Margaritaria* by Mr. Schu- 

 macher. To all these generic names the A. margaritifera 

 of Linne was referred by their respective authors, who do 

 not appear to have been acquainted with either of the sev- 

 eral species which inhabit our waters. 



Those who change the orthography of Anodonta to 

 Anodon, will write the name of this genus Alasmodon for 

 the same reason. One author writes it Alasmidonta and 

 Blainville changes it to Alasmisodonta, without abbrevia- 

 tion. 



But those who 'assume the task of rejecting genera in 

 this family, in order to he consistent, must revert to the 

 principles laid down by Ferussac in his "Essai d'une me- 

 thode Conchyliologique" published in 1807. He redu- 

 ces all the Naiads to the genus Unio, and the remain- 

 ing parts of his system, chiefly, correspond with this view 

 of the subject. Mr. Sowerby in the Zool. Journal, 1824, 

 has made the same proposition, though in his "Genera" he 

 retains Anodonta, Iridina, and Hyria, as well as many gen- 

 era in other families, which the same principles of arrange- 

 ment would abolish. Ferussac, however, in his "Tab- 

 leaux Syst." 1822, has concluded to admit four of the gen- 

 era ; viz, Anodonta, Hyria, Unio and Castalia. 



PLATE XXI. 



* Essai d'un nouvcaux systcmc dee habitations des Vers Testace6s, 1817. — 

 The priority of this date would lead ine to adopt the name given by tiiat 

 author, did it not appear that the work was not published for several years 

 after it was printed. It was not known to the naturaliets of thie country, 

 France, Germany or England until the year 1824. 



