316 KANSAS UNIVERSITY SCIENCE BULLETIN. 



Interior: Pseudocardinals fairly large, erect, pointed, rag- 

 ged, double in the left and single in the right valve. Laterals 

 short, low, heavy, straight, very oblique; interdentum long, 

 broad, and smooth. Anterior adductor cicatrix rather small, 

 located in front of the pseudocardinals, much longer than 

 wide, well excavated. Posterior cicatrices small, well im- 

 pressed, distinct. Dorsal cicatrices forming a line on the 

 under surface of the interdentum. Pallial line impressed 

 only anteriorly. Hardly any beak cavity ; cavity of the shell 

 small. Nacre a beautiful white, slightly iridescent posteriorly. 



(Coll. K. S. A. C.) 

 (Coll. Kan. Acd. Sci.) 



C. alherti is limited in range to southern Kansas, Missouri, 

 Indian Territory, and Arkansas. Its distribution in Kansas 

 is limited to the clear-water streams of the southern drain- 

 age. The streams in which it has been found are Fall river 

 (Mead, Popenoe), A^erdigris river (Cragin, Popenoe) , and 

 Neosho river (Fenis) . Even in these streams it is a rare 

 species. 



As compared with specimens before me from the White 

 river, Arkansas, the Kansas form is a much larger, more 

 inflated and massive shell, with smaller muscle cicatrices. 

 Doctor Call described specimens from the Neosho and Verdi- 

 gris rivers as a new species ( Unio popenoi) , but later on 

 worked out the synonomy and placed it under U. alherti 

 (5-6) . 



There is no other Unio in Kansas which can be confused 

 with this one. The peculiar markings of the epidermis and 

 the extreme flattening of the beaks for about one-third the 

 distance vertically across the disk is very characteristic. 



Genus OBLIQUARIA ( Rafinesque, 1820) Simpson. 



"Shell inflated, solid, oval, ending in tolerably sharp point 

 behind, having a row of large compressed longitudinal knobs 

 running off from the beaks to the center of the base,- those 

 on one valve alternating in position with the knobs of the 



