150 AMERICAN JOURNAL 



NOTES ON MOLLUSCA COLLECTED BY DR. F. V. HAYDEN, 

 IN NEBRASKA. 



BY GEORGE W. TRY0N, JR. 



Our fellow-member Dr. Hayden, during his recent rapid geo- 

 logical survey in Nebraska, for the General Land Office, col- 

 lected a few species of Unionidce, etc., which have been submit- 

 ted to me for examination. Unfortunately the collection repre- 

 sents but few of the species known heretofore to inhabit that and 

 the subjacent States ; yet among them are some forms of great 

 interest. 



Nearly all of the Unionidce belong to the species prevalent 

 throughout the Northern and Western States ; but there are, in 

 addition, a few speciesof unexpected occurrence. Of these may 

 be named, as most remarkable, U. nigerrimus, Lea, and U. Ru- 

 tersvillensis of the same author, both Texan species, and U. 

 Mississippiensis, Conr., a shell described from the State of Mis- 

 sissippi. These three species were all collected by Prof. Hayden 

 at Falls City. This locality also furnishes to us the new Kansas 

 species U. TopeJcaensis, Lea, a very interesting form, readily 

 distinguished by its curious close biradiating undulations. 



At Nebraska City was obtained a single but perfect valve of 

 Unio pressus, Lea, a shell native to the great lakes, and not in- 

 frequent in the Erie Canal at Albany, N. Y. It has not hitherto 

 been found nearly so far west. 



A list of species collected and the localities is hereunto sub- 

 joined. Specimens have been kindly placed in our Museum by 

 Dr. Hayden. 



Big Blue River, Gage Co., Nebraska City. 



Nebraska. Unio ^^ g a y. 



Unio anodontoides, Lea. a late-costatus, Lea. 



" ventricosus, Barnes. " gracilis, Barnes. 



" rectus, Lamarck. " anodontoides, Lea. 



" alatus, Say. u pressus, Lea. 



Iowa Creek. " rubiginosus, Lea. 



. 7 t, .. T Anodonta undulata, Say, 



Anodonta Footiana, Lea. ' J 



Unio ventricosus, Barnes. 



" luteolus, Lam. 



