MICHIGAN ACADEMY OF SCIENCE. 23 



Clams. 



Anodonta grandis footiana (Lea). Common; distribution similar to that 

 along the unprotected shores. 



Lampsilis luteola (Lam). Frequent; distribution similar to preceding 

 species. 



Anodonta marginata (Say). Infrequent; found mainlj^ in deep littoral 

 zones; found in shallow water and in more protected situations than the 

 preceding forms. 



Lampsilis nasuta (Say). Very infrequent; distribution similar to the first 

 two species. 



Primary species. 



Campeloma decisum (Say). Very abundant; distribution similar to that 

 on unprotected shelves, only more abundant thruout. 



Planorhis hicarinatus, var approaching portagensis Baker. Shelf form. 

 Abundant; from a depth of about 15 cm. to near the edge of the shelf. Most 

 abundant in soft bottomed places at a depth of 65 cm., or in places pro- 

 tected by outer bars. 



Sphaerium acuminatmn (Prime). Frequent; thruout the deeper portions 

 of the shelf. 



Planorhis campanidatus smithii Baker. Infrequent; most numerous in 

 about 40 cm. of water, in places where bottom was soft. 



Lymnaea emarginata, var. approaching angulata (Sowerby). Shelf form. 

 Infrequent; most numerous in about 40 cm. of water in places where there 

 was a superficial crust. 



Secondary species. 



Planorhis hicarinatus, var., juvenile. Juvenile specimens, which were prob- 

 ably both the offspring of the shore form and of the deep littoral varieties, 

 were abundant in similar situations to the adult shore form, altho usually 

 in somewhat shallower water. 



Physa ancillaria parkeri (Currier), juvenile. Quite abundant; mainly in 

 5 to 15 cm. of water on pebbles, etc., and on the firmly cemented bottom. 



Lymnaea emarginata angulata (Sowerby), juvenile. Common in similar 

 situations to the shelf form. 



Planorhis parvus Say. Common; mostly in protected places in water from 

 10 to 35 cm. in depth. Most abundant at about 20 cm. 



Valvata tricarinata (Say), and var. confusa Walker. Quite common; in 

 similar situations to the preceding. Most numerous in about 30 cm. of 

 water. 



Amnicola limosa (Say). Quite infrequent; in similar situations to the 

 preceding. 



Planorhis campanulatus smithii Baker, juvenile. Infrequent; along with 

 the adults. 



Physa ancillaria, var. approaching magnalacustris Walker. Very infre- 

 quent; mostly in about 20 cm. of water. It appeared that some of the off- 

 spring of the deep littoral Physa ancillaria parkeri remained on the shelf 

 and became this form, as has been mentioned in a former paper in regard 

 to the forms in the outlet of Maple River (6). Air-breathing, juvenile speci- 

 mens in the laboratory developed into the same form. 



Physa gyrina Say. Very rare; a single specimen was obtained in 25 cm. 

 of water off Pine Point. ' 



'This species, Planorhis deflectus, and Ancylus parallelus were not examined for the Durpose of 

 determining whether they breathed water or air, but it seemed probable that they did the latter, as 

 all of the other pulmonates, including PUmorbis parvus, appeared to do so. 



