44 THE NAUTILUS. 



U. glans Lea. The Clinton livei* at Pontiac, 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. 



U. gracilis Bar. Common. kSpecimens from tlie River Rouge, 

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

 Detroit River are much smaller, showing tl>e unfavorable character 

 of their surroundings. 



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

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

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

 UnionidjB Miss. Valley) credits the si:)ecies to Michigan, 



U. h'lrtlandianus Lea. Cited by Call from the Grande River (loc. 

 cit.). 



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

 Kent County. A specimen received from him agrees in foi'm and 

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

 does not, however, seem to differ from U. undulatus excejot in the 

 more highly develoi:)ed character of the folds. 



U. ligamentinus 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 Lara. Very abundant everywhere and exceedingly 

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

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

 more or less tinged with pink toward posterior portion. 



TJ. viultiradiatus Lea, Appears to occur generally through the 

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

 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. nasutus Say. Occurs all over the State. Specimens from the 

 Detroit River are small and quite thin. 



TJ. 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 species. It is now in the museum 



