164 MOLLUSCA. 



sedge marshes and Turtle Bay (7, 8) at Sand Point are striped trans- 

 versely, much as Lymnaea palustris zebra except that the stripes run 

 at right angles to the usual direction of the bands on that form. 

 Other specimens collected in Turtle Bay are considerably broader 

 than normal. An example measures: altitude 28mm., width 11mm., 

 aperture length 14.25mm., aperture width 7mm. Those from the 

 perennial swamps on Sand Point and Stony Island (19) are, on the 

 other hand, large, elongate and very often strongly but irregularly 

 malleate. One of these measures: altitude 29.25mm., width 10.5mm., 

 aperture length 12.5mm., aperture width 7mm. Some of the shells 

 from these swamps on Stony Island are, in addition, somewhat scali- 

 form, with the suture quite deeply impressed. 



61. Lymnaea refiexa, var. walkeri Baker. — The scaliform variety 

 was found in small numbers with the typical shells in two of the sedge 

 marsh habitats (7) and in Turtle Bay (8) at Sand Point. 



Lymnaea sp? — Juvenile specimens, too young to identify, were 

 obtained in a temporary swamp (18) and off Dune Point (15) at Rush 

 Lake. 



Planorhidae. 



62. Planorbis bicarinatus Say. — This species appeared to be very 

 rare in the region studied as only four specimens were obtained. One 

 of these was brought up on the nets of the fishermen from deep water 

 off Sand Point (1), the other three were found among algae, principal- 

 ly Vaucheria, along the shores of the Pigeon River (21). The speci- 

 men from Sand Point is pure white and very sharply carinated; the 

 specimens from the river are considerably roughened by the growth 

 lines. The largest of the latter measures: greater diameter 13.25mm., 

 aperture length 7mm., aperture width 6.25mm. 



63. Planorbis trivolvis Say. — ^This shell was widely distributed 

 and quite abundant in the region studied. It was found as follows: 

 at Sand Point, on decaying sedges and driftwood in the sedge marshes 

 (7) and in Turtle Bay (8), on hly-pads in the lakes (9, 10) and on 

 leaves on the bottoms of the perennial inland swamps (19); on North 

 and Stony Islands, on driftwood, etc., in the protected swamps along 

 both the rocky and sandy shores (4, 7) and in the perennial swamps 

 (19) ; at Caseville, in a sedge marsh (7) on the Bay near the mouth of 

 the Pigeon River, among algae thruout the river itself (21, 23) and 

 on lily-pads and driftwood in the ox-bow pond (22), and in the "dead 

 waters" (24) off from it ; and at Rush Lake, in the perennial swamps 

 (19), on lily-pads in the lake where the bottom was mucky (11), 

 in the wet places in the sedge marshes (12) and in a county drain (17). 



