78 AN ANNOTATED CATALOGUE 



ti'ibution ; from New York to Georgia ; to Texas and as 

 far north as the Minnesota river. Shells brightly rayed 

 with green are found associated with those in which the 

 rays are obsolete or entirely wanting. Some of its forms 

 closely approach those of 17. luteolus Lam. 



Unio capax Green. Rare : Mississippi river, Burling- 

 ton, " Muscatine" (Witter) ; Iowa river at Iowa City. This 

 form is closely allied to U. ventricosus Barnes. 



Unio coccineus Lea. Common. Shells from the Iowa 

 and Raccoon rivers 'ire often beautifully rayed ; some of 

 those from the latter stream also have a delicate roseate 

 nacre. Several specimens collected at Des Moines cor- 

 spond to the form described by Ward as U. gouldianus. 



Unio cooperianus Lea. Little is apparently known of 

 this species in Iowa. It ranges from the " Ohio river at 

 Cincinnati to the Mississippi river at Muscatine" (Call). 



Unio cornutus Barnes. Abundant in the Iowa and Mis- 

 sissippi rivers. Many from Iowa City are so closely rayed 

 with dark green as to entirely obscure the lighter portions 

 of the epidermis ; while some from the northeastern part 

 of the state are uniformly yellow, and devoid of rays. 



Unio crassidens Lamarck. Iowa and Mississippi rivers : 

 rare. 



Unio donaciformis Lea. Iowa, Mississippi and streams 

 of eastern Iowa generally : common. Ranges north to Fort 

 Snelling. U zigzag/ Lea and this species are synonymous. 



Unio dorfeuillianus Liea. Abundant at Iowa City. This 

 species is so closely allied to Unio puslidosus that it is often 

 with difficulty that the two forms are distinguished. Oc- 

 curs also in the Minnesota river at Fort Snelling. 



Unio ebenus Lea. Common in the eastern part of the 

 state. 



Unio elegans Lea. Very abundant at Iowa City. "Rather 

 rare ; Mississippi and Cedar rivers " (Witter) . It ranges 

 as far north as the Minnesota river. 



