THE NAUTILUS. 75 



the Uniones collected by myself in Texas, during two visits some 

 years ago. 



In the matter of synonyms I have mentioned only such indis])u- 

 table facts as have forced themselves to my notice while identifpng 

 the specimens in hand. Far more extensive name duplication 

 exists in many cases. 



It has been obvious to me for years that Lea's system of sections 

 founded on contour, for the classification of Unionidce, is hopelessly 

 and radically wrong. It builds up false groups in about nine cases 

 out of ten. Lea doubtless knew this as well as we, intending his 

 system merely to be a convenient working guide. In this case, as 

 in most others, the natural system will supercede the artificial, as it 

 will, when well worked up, be found vastly more convenient. 



One of the main characters of the new system will be the sculpture 

 of the beaks, which is greatly varied in the different types, and 

 remarkably constant specifically. The importance of collecting 

 yoxing Avith old specimens cannot be too strongly impressed upon the 

 field naturalist. The character of being Avinged over the hinge- 

 ligament is of minor importance. Lea's alate group including a 

 number of very diverse types. 



Among the more prominent groups represented in the collection 

 here commented on, are the gfro??^ 0/ U. plicatus ; the group of U. 

 parvus (including parvus, Bealei, Texasensis, Sayi, camptodon, etc., 

 etc.) ; the group of U. pustulosus, (including Houstonensis, and 

 nodiferus below, and a number of northern species) ; the group of 

 U.alatus {including purpuratus, alatus, Icevissimus, etc., etc.) 



The species are as follows : 



U. plicatus Les. Leon Cr., Lee Co., Texas. Common and 

 typical at least as far south as the Colorado River at Austin. 



U. trapezoides Lea. Sabine River, Shelby Co., and Neches River 

 near Tyler, Texas. Say's name interruptus has priority, despite 

 Lea's assertion to the contrary, but it had better be dropped on 

 account of the earlier interruptus of Rafinesque, Conrad, et al. 



U. perplicatus Conrad. Big Eddy in Neches River near Tyler, 

 Texas. Apparently distinct from the numerous plicate Uniones 

 of Texas, many of which are mere varieties. 



TJ. Chunii Lea. Big Eddy in Neches River near Tyler, Texas. 

 Belongs to the trigonus group, but is far less angular. It is very 

 variable. 



