THE MOLLUSC A OF GEORGIAN BAY 105 



SESSIONAL PAPER No. 39b 



gates in decaying lily stems and on decaying logs. Recognized easily by large, 

 heavy greenish shell, with short spire and eroded apex, its large, broad, brownish 

 mottled foot and its long tapering tentacles. Color varied by narrow, irregularly 

 placed dark bands crossing the whorls. In dark water it is often rusty brown. 

 Young lighter in colour, lip of aperture thinner and shell has numerous fine lines 

 parallel to whorls. All stages of development from young in the uterus to the 

 adult form are easily obtained. Feeds on decaying vegetable matter. (Pi. XI, 

 Fig. 20). 



Family unionidae. 



Represented by seven species belonging to four genera. 



Genus Lampsilis. 



Two species of this genus are reported. 



Lampsilis ventricosus, Barnes. The single specimen obtained some years ago 

 was identified by Bryant Walker as L. ventricosus canadensis, Lea, conforms to de- 

 scriptions of L. ventricosus and since Simpson (1900) includes canadensis in synon- 

 ymy of ventricosus it is here designated by the latter name. Shell, thick; color 

 yellowish, darker in front. Few faint broad radiations behind, lines of growth 

 coarse, beaks eroded, hinge line straight, nacre white, cardinal teeth double in 

 both valves, lateral teeth single in right valve, double in left. 



Lampsilis luteolis, Lamarck. Very abundant on the slopes of deep pools in 

 sandy channels and along sloping muddy shores. Shell much higher behind the 

 beaks. Beak sculpture consisting of about 13 fine wavy concentric ridges. Color 

 light or dark brown, usually with numerous, sometimes brilliant narrow green 

 rays. Two cardinal teeth in each valve, lateral teeth double in left valve and 

 single in the right, long, curved and lamelllf orm. Nacre white. Hinge line curved. 

 Varies in periostracum which may be smooth and shining or coarsely wrinkled, 

 in outline of shell, in color in prominence and number of rays and in cardinal 

 teeth which are pyramidal or lamelliform. Females inflated posteriorly. Young 

 narrower than adults. A form is common here which is large and heavily shelled, 

 has a dark brown periostracum often with a greenish sheen towards the umbones 

 and is coarsely and closely wrinkled at the margin of the gape. The variety 

 rosaceus which has smooth reddish-brown periostracum and rosy nacre also occurs. 

 (PI. XII, Figs. 23, 26, 30). 



Genus Anodonta. 



Of this genus one species occurs. 



Anodonta grandis, Say, occurs plentifully on steep slopes of sand banks in 

 sandy channels, and also, but less abundantly in the soft mud of sheltered bays. 

 Shell thin, smooth, inflated, hinge-teeth lacking, usually dull in colour. Beak 

 sculpture, four or five concentric ridges with anterior and posterior loops. Varies 

 greatly in color, sometimes dull and almost rayless; at times brilliant, with many 

 green rays. Varies also in inflation of shell and in outline. Forms were found 

 typical of footiana as well as other typical of grandis, s.s., but there were also 

 many intermediates. (PI. XII, Figs. 23, 28). 



