44 THE NAUTILUS. 



the same species," nevertheless it is a distinct advantage to 

 know exactly what Rafinesque in 1831 understood or claimed 

 to be the species that he had described in 1820. 



The author has presented a tentative synonymy of the species 

 represented in the Poulson collection, " if they were recognized 

 and the names dated from 1820." In this suggested arrange- 

 ment, Rafinesque' s genera and subgenera are ignored and all of 

 his species are treated as Unios and synonymy is based entirely 

 on the supposition that they were described as Unios. 



In this, the author seems to have overlooked Rafinesque' s 

 explicit statement, (p. 298), as to his method of compiling hi& 

 Monograph. 



In 1819, Rafinesque had proposed to divide the North Amer- 

 ican Unios, "provisionally," into eight subgenera. In 1820, 

 in his " Monographic," after referring to this fact he says: 



"Since then, having increased my species and verified their 

 characters, it appears to me to be proper to make from them 

 many genera and subgenera, but to humor ("pour complaire") 

 naturalists, who might hesitate to adopt the changes in nomen- 

 clature that the discoveries necessitate, I will give the name 

 of Unio in the second place to all new species, observing to those, 

 who would assign them all to the genus Unio, which thereby 

 would contain more than seventy species, that it would be 

 necessary in the description of the specific characters to repeat 

 those of my new genera, this would render the definitions of the 

 species long and prolix." 



In accordance with this statement, throughout the Mono- 

 graphic he first prints his name for the species in italics and 

 then, "pour complaire," adds in parenthesis and in Roman type 

 the popular or conventional name. 



If, instead of adopting this system, he had in every instance 

 stated in his explanatory remarks that for those who did not 

 adopt his new genera the species would be an Unio, there 

 could be no possible doubt of his intention to use his new gen- 

 eric terms. And, in view of his explicit statement, I do not 

 see how any other inference can be properly drawn from the 

 method that he did adopt. There is not to be found anywhere 

 in the Monographic the slightest intimation that he had eve? 



