Occasional Papers of the Museum of Zoology 5 



longitudinal striping is exhibited in the series and occasional 

 specimens are very conspicuously variegated in this manner. 



14. Lyinn-cca obrussa Say. A few specimens of a rather 

 small form were taken on Charity Island. 



15. Lyiinia-a dalli Baker. A single specimen was found 

 among the elodes from the interior of Charity Island. 



16. Physa ancillavia uiagnalacnstris \\'alker. A character- 

 istic beach form of the Lake Huron shore. Typical examples 

 were founrj on the west and south beaches of Charity Island 

 under drift-wood. It also occurred on Little Charity, and all 

 the shells fouild there seem rather thinner and more trans- 

 parent tlian those from Charity Island, but as none are fully 

 mature, this may not be a characteristic of the adult form. 



17. Physa Integra Haldeman. Quite a number of the solid 

 lake form of this species v.-ere taken on Little Charity and a 

 few immature shells on Charity Island. 



18. Physa heterostropha Say. A few, not fully mature, 

 specimens were collected on the west beach of Charity Island. 



19. Physa sayii Tappan. A single specimen, 19.5 mm. in 

 length, was found on Charity Island. 



20. Physa gyrina Say. A single dead shell, without the 

 apex, from Charity Island is probably referable to this species. 



21. Aplc.va hypiionini (Linnaeus). Found abundantly 

 under drift-wood on the west and south beaches of Charity 

 Island. A few specimens were also found in tlie dried-up 

 water-holes in the interior of the island. 



22. Planorbis tniitcatns Miles. A few specimens of this, 

 the most characteristic species of the Saginaw Bay region, 

 were collected on Charity Island, 



2^. Planorbis canihaniilatiis Say. Abundant on the mud- 

 llats along the edge of the pond in the interior of Charity 

 Island. The specimens are quite uniform in shape and belong 

 to a flat form rather characteristic of the sandy region of the 

 upper part of the Lower Peninsula. It has been seen from 

 several localities and is more closely related to the var. rndcntis 

 Dall than to typical campannlatus. The largest and smallest 

 specimens measure as follows : 



