Bibliographical Notices. 137 



The author, who has been studying these shells for many years, 

 appears to have set out with the determination to make the * Synopsis ' 

 afford the collectors of these shells as little assistance as possible 

 Thus, he does not mention in which of the works of the various 

 authors cited for the names, the shell under consideration is described 

 or figured, or refer to any general work on the subject in which they 

 are described, nor even to the very numerous species which he has 

 himself described and figured for the first time (more than half the 

 species in the * Synopsis ') in the Transactions of the American Aca- 

 demy, which have been collected together into five quarto volumes, 

 under the title of * Observations on the genus Unio.' He merely 

 adds "Lea" after the name, without making any reference to the 

 volume or page or plate of the * Transactions ' or * Observations * 

 in which they are figured and described, so that the student has to 

 look out each species through the various volumes, where the shells 

 are arranged without order as they occurred to hand. 



In the same manner the names in the " Geographical Distribution 

 of the Species " are not accompanied by a reference to the page in 

 which the species occur in the * Synopsis.' Their place in the Syste- 

 matic List can only be found by turning to the *' Index of Spe- 

 cies," which carefully abstains from referring to the place where the 

 species can be found described in the ' Transactions ' or ' Observa- 

 tions,' though this edition of the ' Synopsis ' is now printed of the 

 same size as those works, and may be regarded as a sixth volume of 

 the * Observations.' 



We had hoped that as the author became more acquainted with 

 the difficulties of the subject, he would have obliterated the ill-natured 

 observations he had made on Rafinesque, Say, Barnes, Conrad, 

 Deshayes, and other authors, but his dislike appears to have increased 

 with his knowledge, and in every page we have some special pleading 

 why Mr. Lea's name should be adopted, and that of some other 

 author rejected, forgetting that his successors, not having these per- 

 sonal feelings, will examine the question for themselves and do jus- 

 tice to his predecessors and contemporaries. 



Mr. Lea informs us in this edition, that he has doubled the number 

 of species in his * Synopsis ' by the new species he has described : if 

 only a tithe of the 300 species which he has described as new prove 

 good, which we venture to doubt, knowing how exceedingly variable 

 these shells are in our European rivers, Mr. Lea's name will be handed 

 down to posterity as an active collector and describer of these mutable 

 shells. Mr. Lea appears to have no other idea of arranging the spe- 

 cies, than by taking some leading character, as the general form and 

 kind of surface, and applying it artificially for the divisions of the 

 species of each of the subgenera : — the result is most unsatisfactory 

 and artificial. 



If the shells do not afford good sectional characters, we believe it 

 would have been preferable to have arranged the species in each sub- 

 genus geographically, dividing the numerous American species ac- 

 cording to the two sides of the continent they inhabited, and subdi- 

 viding them according to the great river-system to which they be- 



