54 NOKTH AMERICAN FAUNA. [N'o.22, 



HeinarJLS. — This species is common and quite generally distributed 

 throughout the region between Lake Winnipeg and Hudson Bay. 

 Though its skin is worth but a few cents in trade, the abundance of 

 the animal and the ease with which it is trapped cause it to be much 

 sought for, and many thousands arc annually taken. 



While ast'ending the Echimamish we found muskrats abundant and 

 tame, and we also saw many in the marshy lakes in the neighborhood 

 of Robinson Portage. On account of the abundance of ' rats ' these 

 two localities are favorite trapping grounds of the Indian hunters. 

 The sweet flag {Acunis calamus), a favorite food, abounds in the lakes 

 below Robinson Portage, and the great number of muskrat houses seen 

 there showed the locality to be a favorite resort. We saw many musk- 

 rats while we were descending Hill and Steel rivers. Here they 

 live entirely in burrows in the banks, as the deep water and swift cur- 

 rent render house building impracticable. Piles of mussel shells, 

 showing where the animals had been feasting, were frequently noticed 

 on the banks. The point of marsh below York Factor}- seemed to be 

 the home of a considerable number of muskrats, but as it is frequently 

 overflowed, they are said to seldom survive the winter. In the vicinity 

 of Fort Churchill they were found in but one place — a stream 

 entering the Churchill River a few miles above the post, and there 

 they were rather uncommon. 



A winter following a dry season is said to be very destructi\'e to 

 muskrats. On account of the low water the animals construct their 

 burrows and houses correspondingly low and are often forced out by 

 floods at a season when they are unable to procure food and have no 

 protection from their enemies. 



We collected specimens on the Echimamish, and at Robinson Port- 

 age, York Factory, and Fort Churchill. Young of the year in fresh 

 pelage are darker than adults, but the entire series Ave collected shows 

 much less rich brown than zihttJdcus from x\ew England. 



Synaptomys (Mictomys) buUatus Preble. Northern "Lemming Vole. 



Synaptoiiiiix^Miiiomys) hiillatus Preble, Proc. Biol. Soi-. A\'ash., XV, p. 181, August6, 

 1902. (Trout Rock, near Fort Rae, Mackenzie.) 



We trapped only two specimens of this lemming vole — one at Nor- 

 way House June 21 and one, a female with six embryos, in the swamps 

 bordering Echimamish River June 2.5. 



Lemmus trimucronatus (Richardson). Back Lemming. 



We found this fine species at but one locality, near the mouth of 

 Thlewiaza River, where it was common and where a series of 

 about seventy, comprising adults and young of both sexes, was secured 

 August 4 to 8. A succession of low, flat, boulder-covered areas, which 

 lay between the shore and some shallow lagoons a few hundred yards 

 inland, was occupied by the animals. The ground was dry and well 



