ECOLOGY OF NORTHERN MICHIGAN. 99 



one, quite different from any of the descriloed forms. The occurrence of 

 the Limnaea related to L. sumassi Bd. on -Isle Royale is a very interesting 

 discovery, and, whether distinct or merely a variety of that form, is new 

 to the Michigan fauna. Originally described from British Columl^ia L. 

 sumassi is peculiarly a western species, and its occurrence so far east, if 

 these shells are referred to it, is quite vmexpected. Planorhis bicarinatus 

 striatus Baker has not before been listed in the Michigan fauna, as it was 

 described since the last (1894) general catalogue of the Mollusca of the 

 State was published. It is, however, a form of general distribution through 

 the northern part of the state and occurs occasionally in the southern counties. 

 (Raisin river, Monroe Co. and Orchard Lake, Oakland Co.). The Pisidia 

 are represented by several interesting forms, some of which are probably 

 undescribed species, but the amount of material is at present too meager 

 to justify a decisive opinion. It is a matter of regret that this interesting 

 group was not more largely represented in the collection. The collection 

 from the Porcupine Mountains is n^cessaril}^ largely the same as that made 

 in 1903, and affords no occasion to vary the opinion as to the general character 

 of the fauna already expressed in the report on these collections.* 



The specimens of Cochlicopa luhrica from the hardwood forest, II. 2, are 

 the elongated slender f5rm described by Doherty as morseana. It has not been 

 listed before from this State. Acanthinula harpa and Zonitoides asteriscus are 

 boreal species, the former hitherto found only at Beulah, Benzie Co., Char- 

 levoix and Petoskey, and the latter at Charlevoix. Their occurrence on Isle 

 Royale and in Ontonagon County are the first records for the Upper Peninsula. 

 Pallifera hemphilli W. G. Binn. is a new species for Michigan and a very 

 interesting one. It was originally described from Mount Mitchell, N. C. and 

 Lulu, Hall Co., Ga. Dr. Pilsbry says, "It looks jis though hempMlli might 

 be a Canadian form which extends down the mountains. I have seen it 

 also from the mountains in Pennsylvania." 



*Sixth Report Mich. Acad. Science, 1904, p. 192. 



