Occasional Papers of the Museimi of Zoology 41 



Pisidiiim compressum Prime. Habitats: 4, 5, 6m, 7, 8, lom, 

 27m , 32, 33. Lakes and large streams. 



Pisidinm compresstt^m laevigatum Sterki. Habitat 7m. 



Pisidiuin nicdianum Sterki. Habitats: 6m, 7m, 27m. A 

 ''small form" of the species : 1. 2.6 mm. ; alt. 2.2 mm. ; w. 

 1.8 mm. 



Pisidinm novcboracense Prime. Habitat 26. "Evidently a 

 variety or possibly distinct." Epidermis light straw-color; 

 shells more elongate and with less prominent beaks than usual. 

 A large example: 1. 4.1 mm.; alt. 3.3 mm.; w. 2.7 mm. 



Pisidinm pauperculum Sterki. Habitats: iim, 26, 27m, 

 Living example: 1. 2.2 mm.; alt. 2.1 mm.; w. 1.5 mm. 



Pisidinm pauperculum crystalense Sterki. Habitats : 5, 8m. 



Pisidinm panpercnlum nylanderi Sterki. Habitat 5. "Ap- 

 proaching variety nylanderi (Northern Maine)"; 1. 2.4 mm.; 

 .alt. 2.5 mm.; w. 1.9 mm. 



Pisidinm peraltum Sterki, var. Habitat 7m. "Small and 

 of a shape somewhat different from the typical; evidently a 

 •variety." 



Pisidium punctaium simplex Sterki. Habitat 8. 



Pisidinm roperi Sterki. Habitats: 17, 18, 19; temporary 

 swamps. Those from first locality "slightly different, but 

 probably not distinct." A large example: 1. 4.1 mm.; alt. 3.5 

 mm. ; w. 2.4 mm. 



Pisidinm roperi, var. Habitat 16. "A small form, with 

 narrower beaks, which may represent a variety," from sphag- 

 num bog. Largest example: 1. 3.9 mm.; alt. 3 mm.; breadth, 

 :2.2 mm. 



Pisidium sargenti Sterki. Habitat 7. "Not characteristic." 



Pisidium splendidulum Sterki. Habitat 7m. "Small form." 



Pisidium tenuissimum Sterki. "Small." Habitat 7. 



Pisidinm zuriabile Prime. Habitats : 4, 5, 6, 7, 8, lom, 27m. 



