76 Trans. Acad. Sci. of St. Louis. 



10. Alasmodonta deltoidea Lea. Erie Canal. 



11. Alasmodonta rugosa Barnes. 

 Station 10. Typical and of good size. 



12. Alasmodonta pressa Lea. 



Station 10. This species is said to be common in the upper 

 Genesee River, but the writer obtained only one specimen 



and that was both a deformed 



and pathologic individual of 



small size (length 49; breadth 



18; height 29 mill.). The 



whole shell is much shorter 



and more stumpy than the 



typical form and there is a 



A. PRESSA LEA. pcculiiir bulgc at the posterior 



PATHOLOGIC SPECIMEN. gnd. Thc tecth are very long 



and very thin. The accompanying cut is an outline figure. 



*13. Alasmodonta undulata Say. (Walton's list). 



Genus Strophitus Eafinesque. 1820. 



14. Strophitus edentulus Say. 

 Unio ferrugine.a Lea, Walton's list. 



Station 12. One specimen found. (Long Pond and Gen- 

 esee River, Walton's list.) 



Genus Unio Retzius, 1788. 

 *15. Unio gibbosus Barnes. Erie Canal. 



Genus Anodontopsis Simpson. 1898. 



*16. Anodontopsis subcylindraceus Lea. Irondequoit 

 Creek. 



*17. Anodontopsis ferussacianus Lea. Erie Canal. 



Genus QuADRULA (Rafinesque) Agassiz. 1852. 



18. QuADRULA rdbiginosa Lea. 

 Station 10. Common, and showing no little variation in 

 relative lengths and heights. 



