292 KANSAS UNIVERSITY SCIENCE BULLETIN. 



straw to rich yellow, radiate rather obscurely in the young ; 

 the rays hardly visible in old specimens. Epidermis smooth 

 and shining in the young, roughened with dark, continuous 

 lines of growth in old shells ; posterior slope much roughened. 

 Ligament long, rather thick, dark brown. 



Interior : Pseudocardinals double in the left, and single, with 

 sometimes an auxiliary ; in the right, erect, thin, plate-like, 

 slightly serrate at their tips. Laterals long, thin, straight, 

 or nearly so. Anterior large, moderately impressed, elongate, 

 fan-shaped. Posterior scars lightly impressed, confluent, 

 rather large. Dorsal scars irregular as to numbers and posi- 

 tion in umboidal cavity. Pallial line impressed for anterior 

 third or fourth. Cavity of beaks slight, of the shell consider- 

 able. Nacre pearly white, often pink, in the central cavity, 

 quite iridescent. 



This species is distributed over the Mississippi drainage 

 and the Gulf drainage from Florida west into Mexico. It is 

 common in all the Kansas drainage systems, but most abun- 

 dant in the Kansas basin. Its western reported range in 

 the state is Kingman (Call), in the Arkansas drainage, and 

 Wildcat creek, Riley county (Popenoe). It lives preferably 

 in muddy or sandy beds, and is found in rivers and streams of 

 all sizes, often ascending into the smallest tributaries. It is 

 quite active in its movements and is a rapid burrower. In 

 spite of its adaptability to environment, as shown by its wide 

 distribution, L. anodontoides is not a hardy species. It is one 

 of the first to die when kept in an aquarium. 



This species was among a lot of Unios found in the Pleisto- 

 cene on Hell creek, in Gove county, of this state, by Mr. H. 

 T. Martin, of Kansas University. The specimens turned 

 over to me were typical anodontoides^ and were in a fair state 

 of preservation. Mr. Martin states that these forms are un- 

 doubtedly of Pleistocene and not recent origin, and were 



