380 ANNUAL OF SCIENTIFIC DISCOVERY. 



the continent over all the other genera, both as to numbers and universality 

 of distribution. The genus Mulleria (Acoslea, D'Orb.) has only been found 

 in the tributaries of the Magdalena, iu New Granada. 



In reflecting on the profusion of this kind of animal life in the United 

 States, the naturalist is astonished at the great number of forms character- 

 istic of the various species; and he is the more struck with the extent of ir, 

 when a comparison is made with the small number of species which inhabit 

 the continent of Europe, there not being in the fresh waters of that quarter 

 of the globe more, perhaps, than ten species; viz. seven Unioncs, one Mar- 

 yaritana, one Monocondylcca, and one Anodonta. Mr. Lea stated that he had 

 taken great pains to procure specimens from all parts of Europe, and he was 

 satisfied that there were ninety-eight synonyms made by European authors 

 for the single species of Unodonta cygnea, Draparnaud, the Mytilus cygneus of 

 Linnseus, and the synonymy is nearly as profusely erroneous in Unio pic- 

 tonun, Unio tumidus, Unio Batavus, and Unto littoralis. 



