X'iv SYNOPSIS OF 



not been successful. That the same idea exists in the construction of species is 

 evident through a great number, but that this idea is returned to the point at which 

 it commenced I am not prepared to admit. The arrangement of the system adopted 

 in this Synopsis, whatever may be said to the contrary, is eminently natural as regards 

 the exo-skeleton or shelly covering of the included soft parts. Although I have 

 examined critically and published descriptions of the soft parts of 254 species of this 

 family, and often dissected 50 to 100 of the same species, I cannot see, as yet, any useful 

 division that could satisfy the student or the adept, which can be made by systematic 

 difference in the organic forms of the soft parts. "With a knowledge of the soft 

 parts of about only a fourth part of the family, is it not unwise to attempt a division 

 for the whole? And again, will it not be a very long time before it will be possible 

 to obtain the complete animal of most of the species? Some of them perhaps 

 never will be obtained by the American or European Malacologist. I am satisfied 

 that eventually, when we shall become sufficiently acquainted with the soft parts 

 of most of the Unionidce, the best division into genera will be founded on the 

 diverse forms of the branchial uteri. I have now examined carefully 254 species, 

 mostly with charged uteri, and I have come to the conclusion that any safe division, 

 founded on the characters of the functional soft parts, must be based on this very 

 important organ, which shows so distinct and varied a conformation, often involving, 

 as it does, the form of the massive envelope. 



In regard to the making of species a few remarks may be made here. That 

 there has been great abuse of it there can be no doubt. Think of the nearly 250 

 synonyms for the seven or eight species of the Family Unionidce living in Europe! 

 Many very able writers have deprecated this folly and ignorance, but it still goes on. 

 In the United States we have such an extraordinary development of this form of 

 shell life, that many European writers find it difficult to give us credit for our real 

 disposition — at least I speak for myself — of keeping down our species as much as 

 possible. The nomenclature is becoming truly embarrassing, and there seems to be 

 no avoidance of it. We have by no means exhausted the discoveries of these forms 

 in Georgia, Alabama, and Mississippi, which States seem to be, and particularly 

 Georgia, the centre of this form of Malacological life. 1 JSTo species has ever been 

 described by me without the greatest care and all examination used that was possible. 

 "When not well satisfied of distinctive characters, I have laid the specimen aside in 

 hopes of better light, and I have by me now many of which I am uncertain as 



1 The late Bishop Elliott, who did so much to develop the Unionidse of Georgia, observed to me in 

 one of his letters, that almost every stream seemed to afford him new species. 



