368 KANSAS UNIVERSITY SCIENCE BULLETIN. 



Kej to the Kansas Unionidse. 



This key is a purely local and artificial one. It is intended only to supplement the figures 

 and descriptions in the identification of species. 



I. Shell Rough. 



A. Shell hearing undulations across the disk. 



a. t'ndulations confined to the posterior slope, laterals not present. 

 phynota costata, 



b. Laterals present. 



1. Dtnbones high and full. Quadrula plicata. 



2. Umhones fairly high and foil; shell decidedly broader behind than 



before; plicatious regular. Quadrtila perpticata. 



3. Umbones compressed. 



l l , Umbones smooth except for slight ridges on their tip-. <jiut<!- 



ridn undulata, 

 2*. Umbones very pustulose. Quadrula heros, 



B. Shell ornamented with coarse concentric folds on the lateral slopes, very heavy; 

 beaks placed far forward. Pleurobema cica(riC08itm. 



C. Shell with a very pronounced nmboidal ridge, which is ornamented with several 

 large, irregular nodnles. 



a. Shell decidedly elongate, pseudocardinals small. Quadrula cylitidrica. 



b. Shell roundly quadrate, pseudocardinals large. Quadrula metan 



D. Shell elongate with BtroDg nmboidal ridge, tubercular anterior, generally brokenly 



plicate posteriorly. 'J'ri toy onto tuhft <-ut<tta. 



E. Shell roundly triangular, lateral slopes bearing a single radial row of erect tuber- 



cles 3 i> iu number. Obliquaria reflexa. 



F. Shell pustulose. 



a. Pustules arranged in two radial rows on either side of a shallow radial furrow. 



1. Pustules confined to the dorsal half of the disk, shell produced posteri- 

 orly. !'!• u robt hi" •< topus. 



2. 1' oeral ly extending over the surface of the disk, shell quadrate. 



ula lachrymose* , 



b. Pust ules irregularly scattered over the disk, shell sometimes almost epustulate. 



Group of Quadrula pustulosa. 



II. Shell Smooth. 



A. Neither laterals nor pseudocardinals pre 



a. Beaks hardly apparent. 



1. Shell small and cylindrical. A nodonta gracilis, 



2. Shell large and circular in outline. Anodonta suborbiculata, 



b. Beak- of moderate inflation and elevation. 



1. Shell large, hinge line straight in front of the umbones, relation of 



length to breadth as - is to ). Group of A nodonta grandis, 



2, Shell of only moderate size, hinge line slightly incurved in front of the 



beaks; shell drawn out to a point posteriorly. Anodontoidea fervs- 



c. Shell with extremely high and iutlated beaks. A 



B. Laterals absent, pseudocardinals present as mere rounded knobs. Steophitu 



tulus. 



C. Pseudocardinals well developed, laterals indicated only by one low ridge on each 

 valve. Shell often aiate. Symphynoi ata* 



D. Laterals and pseudocardinals present. 



a. Shell a late. 



1. Nacre pinkish in the cavity and over the dentition of the shell, pseudo- 



cardinale small, rounded knobs. LampsilU gracilis, 



2. Nacre deep purple pink all over the Interior of the shell. 



1'. Shell very thin, pseudocardinals extremely lamellar. Lamp- 

 silis I" visa 



Budocardioals of moderate size and typical form; shell 

 square posteriorly. Lampiili* alata. 



8*. Shell only slightly alate, inflated, subsolid, pseudocardinals 

 of typical form, epidermis generally black. Lamptilit pur- 

 lin ' a 



