Occasional Papers of the Museum of Zoology 43 



the umbones; umbones golden yellow. An example: 1. 108.9 

 mm. ; alt. 61 mm. ; w. 42.8 mm. 



Lasmigona compressa (Lea). Habitats: 10, 31, 33. Shells 

 in soft and mucky bottom of Jackson Lake remained near sur- 

 face, although younger specimens acted as did other species 

 and buried themselves several inches below the surface, leav- 

 ing a funnel-shaped hole to obtain water. Specimens beauti- 

 fully rayed with olive-green on a background of dull gold ; 

 adults darker and with wing proportionately less evident than 

 in younger specimens. Largest: 1. 101.9 mm.; alt. 53.4 mm.; 

 w. 28.6 mm. 



Lasmigona costata (Raf.). Habitats: 8, 33. The most abun- 

 dant unione, wherever found. Edge of the mantle ofteij con- 

 tained very irregularly shaped pearls about size of number 4 

 shot; known locally as the pearly clam. Largest: 1. 172 mm.; 

 alt. 96.1 mm. ; w. 59.2 mm. ; average : 150.3 mm. ; alt. 82.4 mm. ; 

 w. 43.3 mm. 



Anodontoides ferussacianus buchanensis (Lea). Habitats: 

 10, 31, 33. Specimens from the last two localities small and 

 deformed; those from Jackson Lake quite large and heav}^ 

 beautifully rayed with Hght green. The largest : 1. 79.3 mm. ; 

 al.t 40.8 mm.; w. 29.1 mm. 



Anodonta grandis footiana Lea. Habitats: 8, 25, 33. Streams 

 and river invasions. Shells from Hancock Creek (25) light- 

 colored and dwarfed; one measured: 1. 49.3 mm.; alt. 25.2 

 mm. ; w. 14.5 mm. Those from the other two localities larger 

 and darker colored ; example : 1. 83.2 mm. ; alt. 42.4 mm. ; w. 

 28.1 mm. Beaks more or less eroded. 



Anodonta marginata Say. Habitats : i, 5, 10. Lake species. 

 Those from Jackson Lake ( 10) large and lanceolate ; an exam- 

 ple: 1. 120.5 mm.; alt. 60.3 mm.; w. 41.9 mm. 



