122 THE NAUTILUS. 



published in 1852 and gave a new figure of the type, (fig. 108) 

 and also presented his own description of the form as he under- 

 stood it, which he illustrated by two figures under one number, 

 (fig. 106). Both his description and these figures are excellent 

 and represent a well marked form, which is abundantly found 

 in the southern states from Alabama to Arkansas. He also re- 

 tained the synonymy given in 1862. 



In this work he referred incrassata to Lithasia and gave a new 

 and better figure of the type. 



In the Conchologia Iconica, (1863), Reeve followed Binney 

 in uniting coarctata Lea and exilis Anth., but considered lima as 

 specifically distinct. His figure of coarctata represents exilis and 

 was drawn from the same specimen figured by Binney, as 

 Anthony's type. 



In 1869, Dr. Jarnes Lewis, (Am. Jour. Con., V, p. 34), from 

 the examination of a series from the Coosa River in the Wheatley 

 collection, came to the conclusion that "all the probabilities of 

 the case point very strongly to the supposition that the true 

 coarctata is a young shell from the Coosa River which, when 

 mature, received the name^owderosa." While express!} 7 refus- 

 ing " to decide any question of difference or of identity between 

 ' ponderosa' 1 of the Coosa and of the Ohio system of rivers," 

 Dr. Lewis was evidently very strongly inclined to the opinion 

 that the two forms were specifically distinct. On p. 36, Dr. Lewis 

 also refers to specimens from Corinth, Miss., in the Wheatley 

 collection labeled " coarctata Lea," which seem to be identical 

 with the coarctata of Binney and concludes : " It is needless to 

 add that this species is not coarctata} it is one, which in a care- 

 ful review of this genus, should receive a distinct designation." 



Apparently, Dr. Lewis has long before come to the same 

 conclusion, as Binney states that as early as 1862, there were 

 in the Smithsonian Museum, specimens of his, Binney 's, 

 coarctata from Jackson, Miss., labeled " compressa Lewis." 

 Dr. Lewis, however, never published any description of his 

 compressa and, so far as I have been able to ascertain, never re- 

 ferred to it in any of his writings. 



Later, however, in his "Fresh-water and Land Shells" of 

 Alabama, (1876), he somewhat modified his opinion. In the 



