52 THE NAUTILUS. 



Conrad, who shortly after this time had become quite intimate with 

 Say, so considered it in his " New Fresh-water Shells," published 

 in 1834. So did Dr. Lea, but the opinion of the latter was dis- 

 counted by conchologists because of the well-known enmity which 

 unfortunately had sprung up between Say and Lea. Say himself 

 placed Lea's Unio varicosus as a synonym of his Unio cicatricosus? 

 in the short and exceedingly erroneous Synopsis of 1834. This 

 dictum of Say has been accepted by nearly all conchologists since, 

 but Say had never seen Lea's species, and his idea no doubt arose 

 from Lea having compared his varicosus with the aesopus of Green. 

 Say having shortly afterwards died, this dictum was never corrected 

 by him. 



It is true that Green had in 1827 published his Unio aesopus ; but 

 Say tells us that he had to fort-go at this time (1829) a design of 

 compiling a synopsis of the western Uniones, because of the impossi- 

 bility of procuring books, etc., in his insulated abode, and Dr. Green's 

 article, which was published in a rather obscure publication, no- 

 doubt had escaped his notice. At any rate the assignment of the 

 Wabash as a common habitat of the cicatricosus effectually bars his 

 shell from being the same as Lea's species, as the varicosus does not 

 live in that river. Say's name then, being a synonym of aesopus, 

 cannot be used for Lea's shell. Lea's name, as he tells us himself, had 

 already been used by Lamarck; consequently his shell has no name. 



Turning now to the shells themselves, we find equally as much 

 confusion. There are no less than four distinct species so called to 

 be found in our various museums and collections. Lea himself did 

 not know his own shell very well, since, I am told by Dr. Dall, 

 specimens of genuine varicosus were labeled by him as subrotundus? 

 while on the other hand we are informed by Dr. A. E. Ortmann that 

 a shell labeled cicatricosus, from the Beaver river, Pa., in thp 

 Academy of Natural Sciences, is in reality only an old Unio subro- 

 tundus. In the Conchologia Iconica of Reeve we are given twa 

 plates of this species (figs. 31 and 50) which evidently represent two 

 different shells. Plates and names, therefore, will be given that 

 students may recognize the sundry shells which at present go under 

 the common names under discussion. 



UNIO DETECTUS, new name. Plate II, lower, pi. Ill, upper figures. 

 This is the true varicosus of Lea, whose type shell is not typicat 



