SCAMMON : THE UNIONID/E OF KANSAS, PART I. 327 



A. grandis and its varieties rauge from the upper St. Law- 

 rence and Lake Winnipeg southwest through the Mississippi 

 drainage to Texas. It is our commonest and one of our 

 largest anodons, and is well distributed over all the Kansas 

 drainage areas. Its favorite habitat is the muddy beds of 

 permanent ponds and lakes and slow-flowing streams. Some- 

 times, however, the species becomes established in large, 

 rapidly flowing, but not rocky streams. It is abundant in 

 the lakes formed from old river-beds of the Missouri river 

 along the northern part of the east boundary of the state, 

 but it is not present in similar bodies of water along the Kan- 

 sas river near Lawrence. 



This is one of the most variable of Anodons, and is pos- 

 sessed of an extensive synonymy on that account. The rela- 

 tion of the height to the length and the umboidal ratio are 

 fairly constant, but the shell varies in almost every character. 

 There is much difference in the thickness of the shell, due to 

 the station, and whole colonies will be found where the 

 epidermis is a rusty black instead of the typical shiny green. 

 There have been numerous varieties of this species described, 

 and the form called var. gigantea is present in Kansas waters, 

 but I think the series of intermediates is so complete that it 

 does not merit even the distinction of a variety. I regard the 

 A. bealii reported from this state as a synonym of grandis. 



Anodonta danielsii Lea. Not figured. 



Anodonta danielsii Lea, Proc. Acad. Nat. Sci. Phila., II, 1858, p. 139. 



Shell long, thin, elongate elliptical, slightly inflated. An- 

 terior margin rounded ; ventral margin gently bowed ; pos- 

 terior margin roundly pointed ; dorsal margin straight or 

 slightly curved, and meeting the posterior margin at an angle 

 of about 155 degrees. Umboidal ratio, approximately 0.28. 

 Umbones prominent but not inflated, and sculptured with 

 two or three sets of rather small, deep, double loops. Um- 

 boidal slopes gently rounded. Epidermis smooth and 



