GOSS' LEMMING MOUSE 



107 



in the woods. A. H. Howell of the United States Biological Sur- 

 vey has reported this form present in considerable numbers at 

 Horseshoe Lake, St. Charles county, Missouri, towards the latter 

 part of April. Concerning this observation he reports as follows: 

 "A large colony had occupied a low marshy meadow close to the 

 Mississippi River. At the time of my visit the water in the river 

 was very high, and the meadow was overflowed to a depth of 

 12 to 18 inches. The mice had been driven from their burrows 

 by the high water, and were hiding as well as they could on tus- 

 socks and under patches of floating debris. When disturbed they 

 ran rather freely over the submerged vegetation and swam freely, 

 but they were easily overtaken. Many had been killed by dogs or 

 other predatory animals, and I was able to get as many specimens 

 as I needed by catching them in my hands. The burrows in this 

 meadow were on the little hillocks, the entrances near the top. 

 Thus they are probably dry except in times of very high water. 



FIG. 27. Map showing locality records of 



1. Goss' Lemming Mouse (Synaptomys cooperi gosstt). 



2. Prairie Harvest Mouse (Reithrodontomys megalotis dychei). 



The entrances are perfectly open and not concealed under vege- 

 tation as is the habit of Synaptomys cooperi in the eastern states. 

 Well-beaten runways extended out from the burrows and under 

 the dead vegetation." 24 



l, A. H., Mammals of the Middle Mississippi Valley : Proc. Biol. Soc. 

 Wash., XXIII, 30, 1910. 



