6 University of MicJiigan 



Largest, altitude (bo(l\' whorl) 5.5; greater diameter, 14; 

 lesser diameter, 10.5 mm. 



Smallest, altitude (body whorl) 4.5 ; greater diameter, 10.5 ; 

 lesser diameter, 8 mm. 



24. Plav.oi'bis antrosus striafits Baker. A single specimen 

 was collected with the campanulatus from the pona on Charity 

 Island. 



25. Plaiiorbis pamis Say. Two specimens only were col- 

 lected on Charity Island. 



26. Segmcntina crassUahris ^^'alker. A few from Charity 

 Island. 



27. Goniohasis livesccns (Alenke). The solid, livid form 

 of this species, characteristic of the Great Lakes, was found 

 abundantly on the beaches of both islands. Those from Charity 

 Island were collected on rocks off the west shore in from 12 to 

 20 inches of water. 



28. Caiiipelonia rnfum (Ilaldeman). A few dead speci- 

 mens of this species were found on the south beach of Charity 

 Island. 



29. Lciinpsilis ventricosa canadensis (Lea). This depaup- 

 erate form characteristic of the Great Lakes occurred in con- 

 siderable abundance on the sandy beach at Light House Point, 

 Charity Island. 



30. Lampsilis Inteola rosacea (DeKay). The dwarf form 

 of this species characteristic of the Great Lakes, though usually 

 lacking the colored nacre of the typical rosacea, can not other- 

 wise be distinguished from it and must bear DeKay's name. 

 It is apparently abundant along the shores of the islands. A 

 few of the specimens collected were typically colored. 



31. Lampsilis nasnfa (Say). A few were collected on the 

 shore of Clrarity Island. 



32. Unio gibbosus Barnes. A few examples of the char- 

 acteristic small Great Lakes form were found on Charity 

 Island. 



33. Strophitiis edcntulus (Say). A single valve of an 

 immature specimen of tliis species was picked up on the beach 

 of Charity Island. 



