THE NAUTILUS. 65 



have not sufficieut authentic material to justify making such dis- 

 tinction at present. 



A. imbeciUs Say. Southern part of the State. 



A. lacustris Lea. Cited by De Camp from the Grand River. 



A. maryatana Lea. Cited as such by De Camp from Pentwater. 

 A. subinflata Antb., described from Michigan specimens and A. 

 Houghtonensis Currier, from Houghton Lake, Roscomraon County, 

 where it still is found in abundance, are referred here as synonyms 

 by Lea. 



A. modesta Lea. Originally described from a specimen collected 

 near Kalamazoo ; this species has been found in other localities in 

 the southern part of the State. It is closely related to A. mbcylin- 

 dracea Lea. 



A. ovata Lea. Specimens referred to this species indicate a gen- 

 eral range over the State. A. subarujulata Anth. is considered syn- 

 onymous by Lea. 



A. pepiniana Ijea. Cited by Miles. Also by Gould from the 

 north shore of Lake Superior. I am indebted to Dr. De Camp for 

 two specimens from Crooked Lake, Emmet County, which he refers 

 to this species and which agree fairly with Lea's figure. They may, 

 however, be young A. Footiana. Another specimen received from 

 him, collected in Houghton Lake, Roscommon County, is probably 

 a half-grown A. Houghtonensis Currier. 



A. plana Lea. Southern part of the State. This is the largest 

 Anodon we have, and attains considerable magnitude in favorable 

 localities. 



A. sabnonia Lea. Southei'n part of the State. Specimens from 

 Maple River, Clinton County, ui-e much larger and heavier than 

 those from Ohio. 



A. Sehafferiana Lea. Cited by Miles, Currier and De Camp. 



A. subcylindracea Lea. Common everywhere and very variable. 

 Some forms seem to exhibit sufficiently j)ersistent peculiarities to 

 justify giving them varietal rank. 



A. subgibbosa Anth. Originally described from Black Lake, 

 Holland, Michigan. It also occurs in Mono and Muskegon Lakes 

 at Muskegon, where it is not uncommon. 



Sphcermm simile Say. Common all over the State. 



S. aureum Prime. The types are supposed to have been brought 

 from Lake Superior by the Agassiz expedition. Cited by De Camp 

 from Charlevoix County. 



