THE NAUTILUS. 



VOL. XXII. MABOH, 1909. No. 11. 



PISIDITJM IN MASSACHUSETTS. 



BY REV. HENRY W. WINKLEY. 



During the past two summers the writer has had opportunity to 

 collect in various places in Massachusetts, and Pisidium has yielded 

 some good series. The species have just been determined by Dr. 

 Sterki, with the following results: 



D;ilton. in the Berkshire Hills a brief visit in early spring 

 yielded compressum and abditum. 



Newton, Upper Falls, gave at one visit variabile, aequilaterale, 

 pauper culum, affine and fe.rrugineum. 



Woburn, in a small outlet to Horn Pond, had compressum, abdi- 

 tum and ajfine. 



Concord, near the famous battlefield, shows variabile, abditum, 

 compressum. 



Wareliam is at the head of Buzzards Bay, almost on Cape Cod. 

 It is an important place in cranberry culture. Considerable mate- 

 rial was obtained from ditches in the cranberry bogs. The species 

 variabile and abditum both show local peculiarities; ferrugineum also 

 occurs in the bogs. A trout brook in the woods gave excellent sets 

 of variabile, with abdifum quite rare. 



Thi', Agawam River at East Wareliam is one of the richest col- 

 lecting grounds I know. Pisidium is not abundant, but is peculiar. 

 Dr. Sterki writes of variabile: " Rather different from the common 

 form, and representing a variety if found at other places," another 

 form similar yet distinct. 



Danvers, my present home, proves an excellent region for this 



