THE NAUTILUS. 107 



LYMN^IDJE OF AROOSTOOK COUNTY, MAINE. 



BY OLOF O. NYLANDER. 



In recording some additional notes on the Lymnaeidae of Aroostook 

 County, I have followed Mr. Frank Baker's valuable work on the 

 Lymnseidoe of North and Middle America. Galba umbilicata is the 

 Limnsea humilis and G. obrussa tlie L. desidiosa of my previous lists. 



Galba umbilicata C. B. Adams. Fine specimens of this species 

 were common in damp places and ditches along the roads in Caribou 

 and surrounding towns. 



Galba obrussa Say. This variable shell is common in the Aroo- 

 stook River. The following varieties are most prevalent : 



Galba obrussa penivsula "Walker. Specimens were collected in 

 the southeastern part of the town of Castle Hill, in wet places along 

 the road. 



Galba obrussa exigua Lea. Common on rocks at low water in 

 Aroostook River. Many colonies were found in Caribou stream, 

 and some are exceedingly variable, hardly two specimens being 

 exactly alike. 



Galba obrussa decampi Streng. A common fossil in the marl de- 

 posits of Aroostook County. Living specimens were found in a 

 small brook, tributary to the south branch of Caribou stream in 

 Woodland and in Salmon brook. 



Galba emarginata Say. Many colonies were found in Fish River. 



Galba emarginala mighelsi W. G. Binney. Square Lake, Cro?s 

 Lake, Eagle Lake and Portage Lake, all on the Fish River. The 

 specimens from Square Lake aie typical of this variety, and are the 

 largest and finest specimens known. 



Galba oroueiisis Baker. A large colony of this species was found 

 in Caribou village where the Caribou stream enters the Aroostook 

 River. The specimens were found on rocks at low water. The 

 color of tliL' animal is bluish-black or mouse color. 



The Caribou stream is full of rubbish from the starch factories, 

 saw-mills and grist mills, and the refuse of the village which fur- 

 nishes the G. oronensis with abundance of food. There is one 

 potato-starch factory about three hundred feet from the shells, and 

 sometimes the colony is nearly covered with the refuse from this 



