1897.] NATURAL SCIENCES OF PHILADELPHIA. 215 



resent all of the above named localities except GrafFensburg. Speci- 

 mens from the latter place were examined by the author. 



The hunters in Sullivan and adjoining counties deny the existence 

 of this rat in that region. I could find no signs of them around 

 Eaglesmere. There are undoubtedly connecting colonies of this 

 species along the Blue Mountains from Harrisburgto Massachusetts. 

 Links in this chain have been found at Greenwood Lake, New Jer- 

 sey, and on the Hudson Highlands, New York. It remains for future 

 investigators to trace their range over the intermediate region and 

 demonstrate the distribution of this large mammal throughout the 

 oldest and most populous mining region of North America, whose 

 very existence as a living species was unknown to naturalists as late 

 as the year 1893 ! 



21. Mus musculus L. House Mouse. 



The common name given this little pest is by no means specific of 

 its habitat. Mr. Ingersoll secured a series of 42 in Juniata, Hunt- 

 ingdon and Blair Counties, nearly all of which were taken in fields 

 distant from houses or outbuildings. They were especially numer- 

 ous in upland meadows, in the runways of Microtus and Blarina. 

 This experience is, however, exceptional, for in other parts of the 

 State I have only occasionally been troubled by them in such places. 



22. Mus decumanus Pallas. Norway Rat. 



This species is quite as much at home in the coal and iron mines 

 of the mountains as in the farmer's barns or the crowded wharves of 

 our great cities. It is sometimes found in the same caves with Neo- 

 toma magister. Which of the two is master I have had no means of 

 determining, but it seems probable that the native animal is able to 

 resist any encroachments on his vested rights. Otherwise it would 

 have long since disappeared from localities it yet inhabits. 



23. Mus rattus L. Black Rat. 



I was unable to secure any recent records of this once common 

 introduced species. 



24. Arctomys monax (L.). Eastern Marmot. 



Abundant in all situations. Specimens from the mountains of 

 the northern counties are intermediates, approaching the Hudson 

 Bay form, Arctomys monax melanopus (Kuhl.). 



25. Tamias striatus (L.). Carolinian Chipmunk. 



26. Tamias striatus lysteri (Rich.). Canadian Chipmunk. 



Chipmunks from Sullivan and Clinton Counties are intermediate 

 between the southern animal and the Canadian form, lysteri. Those 



