44 THE NAUTILUS. 



U. (jlans Lea. The Clinton river at Pontiae, where it was first 

 found many years ago, is the only locality known for this species in 

 the State. Its occurrence there I have been successful in verifying. 



XJ. gracilis Bar. Common. Specimens from the River Rouge, 

 Wayne County, are the largest I have ever seen. Those from the 

 Detroit River are much smaller, showing the unfavorable character 

 of their surroundings. 



C/. iris Say. Cited by Sager, Miles, Currier and De Camp. The 

 latter, however, in a recent letter queries Avhether the Michigan 

 specimens can be distinguished from U. novi-eboraci. Call (Cat. 

 Unionidre Miss. Valley) credits the species to Michigan. 



U. kirtlandianus Lea. Cited by Call from the Grande River (loc. 

 cit.). 



U. Icevissimiis Lea. Cited by Miles, Currier and De Camp. 



U. Leibii Lea. Detroit River, identified by Dr. Jas. Lewis ; mouth 

 of Otter Creek, Monroe County, collected by Jerome Trombly. 



U. latecostattis Lea. Cited by De Camp from the Grand River, 

 Kent County. A specimen received from him agrees in form and 

 in arrangement of the folds with Lea's figure and description. It 

 does not, however, seem to difter from U. undulatus except in the 

 more highly developed character of the folds. 



U. ligavientinns Lam. Southern part of the State. Cited also 

 by De Camp as U. crassus Say. A form with pink nacre occurs on 

 the Grand River (see Lewis, Am. Jour, of Con. IV, 81). 



U. luteolus Lam. Very abundant everywhere and exceedingly 

 variable in size, color and shape. De Camp cites U. siliquoides 

 Bar., from Grand River as distinct. The nacre is occasionally 

 more or less tinged v/ith pink toward posterior portion. 



U. muliiradiatns Lea. Appears to occur generally through the 

 southern part of the State. It is very abundant in the Huron 

 River at Ann Arbor, Mich. A dwarfed form occurs in the Detroit 

 River. The female has the edge of the mantle prolonged in long 

 feelers, similar to those figured by Lea (Observations II, pi. xv, fig. 

 49) in the female of U. radiatus Lam. 



U. nasiitus Say. Occurs all over the State. Specimens from the 

 Detroit River are small and quite thin. 



U. negatus Lea. Sheawassee River, Genesee Co., where it was 

 discovered by Dr. M. L. Leach, who writes that the only specimen 

 he found was sent to" the Philadelphia Academy of Natural Sciences 

 and was there identified as this sjiecies. It is now in the museum 



