On the Identity of Gyclas eleganSj &c. 67 



'''Long, more than one quarter of an inch. It inhabits Lake Cham- 

 plain. It is probable this species attains a larger size than the two spe- 

 cimens from which the above description was taken, and which were 

 found by Mr. Augustus Jessup ; it is distinguishable from the similis by 

 its more rhomboidal form." 



Like many other of Mr. Say's species, that are not accompa- 

 nied by figures, this species has never been properly identified. 



The young of the shell figured in Gould's Eeport as C. similis, 

 has frequently been mistaken, owing to its more or less qua- 

 drangular form, for the C. rhomboidea ; but nearly every cabinet 

 seems to have had this species represented by something dif- 

 ferent. 



In 1851, Adams sent me a Cyclas from Lake Champlain, 

 which he had always looked upon as G. rhomboidea ; on com- 

 paring it with the original description, I found it necessary to 

 differ from him. 



It was not until the summer of 1852, that having collected 

 some C. elegans in the waters of the same lake, I was impressed 

 with the idea that this might be Say's shell. 



On comparing figure 4 on plate I. (which is a true repre- 

 sentation of both the adult and young of C. elegans), with Say's 

 description, it will be found to tally in every respect, especially 

 if \ve take into consideration that the specimens from which 

 Say described, were not adults. 



Say's and Adams's descriptions are not quite similar; Say's is 

 shorter, but it is concise, and contains all that is requisite ; it ap- 

 proaches nearer to Gould's. Say and Adams, however, both 

 make the shells out to be rhomboidal, to have beaks that are not 

 prominent, and to be the same in coloring. 



Little as I like changing a well established name, I think 

 it, nevertheless, obligatory in this case ; and I have hopes that 

 naturalists, taking the three following very forcible reasons, first, 

 that the C. elegans answers the description of Say's C. rhom- 

 boidea; secondly, that it is found in the same locality; and 



