SCAMMON : THE UNIONID^ OF KANSAS, PART I. 301 



ally. Lines of growth fairly continuous. Epidermis dark 

 brown to black, eradiate in old specimens, obscurely marked 

 with wide, dark green rays in young. Ligament long, light 

 brown, stout. 



Interior : Pseudocardinals double in both valves, rather 

 high, very ragged, pyramidal, sometimes directed anteriorly. 

 Laterals of moderate length, thick, high, slightly serrate, a 

 little bowed. Anterior adductor cicatrix ray deeply im- 

 pressed, large. Posterior cicatrices large, moderately im- 

 pressed, wider than long, confluent. Pallial line impressed 

 for the first two-thirds of its length. Dorsal cicatrices large, 

 situated in the cavity of the umbones, variable as to number 

 and arrangement. Cavity of umbones moderate, of shell 

 rather deep, particularly in female. Nacre a light pinkish 

 purple, shiny and iridescent posteriorly. 



L. purpurata is a southern species, ranging as far north as 

 northern Kansas and southern Missouri and from eastern 

 Texas to the Alabama drainage. It is present in all the 

 drainage systems of Kansas, but is most abundant in the 

 southern rivers. It has been found as far west as the Solomon 

 river in the Kansas drainage. 



In the Kansas and Marais des Cygnes areas it is fully as 

 common as L. alata, its lighter shelled northern ally. Its 

 favorite habitat is deep mud, in three to fifteen feet of water. 



Purpurata is not a variable species, although being often 

 attacked by parasites distortions of the shell frequently occur. 

 It probably reaches its maximum size in Kansas waters. Call 

 (4) gives the length of a number of large specimens from the 

 Arkansas river and its tributaries. The length given is from 

 146 to 169.5 mm. A large male shell from the Blue river, in 

 the Popenoe collection, at Manhattan, has a length of 192 

 mm. and a height of 121 mm. The only form with which this 

 may be confused is L. alata, and the differences between these 

 two species are noted under L. alata. 



