March, 1921] Macro-Fauna of Mirror Lake 177 



Order Chelonia. 

 Family TestiidinidcB. 



Chrysemys marginata (Agassiz). The western painted ter- 

 rapin was the only member of the order found here. A small 

 specimen was taken at station 3 in May. One somewhat larger 

 was seen exposed for a short time at the surface and then 

 submerged out of sight beneath the duckweed. A still smaller 

 one was taken in the northwest part of the large pond, north 

 of the bridge. May, 1920. 



Order Ophidia. 

 Family Colubridce. 



Natrix (Tropidonotus) fasciata sipedon (Linn). The com- 

 mon water snake was found to be rare here. One young spec- 

 imen (7 inches long) was caught, and was the only one noticed. 

 It was swimming close to shore near station 3, May, 1920. 



Class Mammalia. 



Order Rodentia. 



Fiber zibethicus (Linn). The muskrat was the only one of 

 the true aquatic mammals present here, and it was rare. There 

 would appear to have been a dearth of appropriate situations 

 and materials for home building, although the shallowness of 

 the water and the possibility of constructing burrows under 

 overhanging banks which existed at some places probably were 

 favorable conditions. Whether there was only one or two, or a 

 few more present could not be ascertained. One was seen to 

 swim straight across a portion of the east end of the large pond, 

 and then submerged. Efforts to locate it were futile. On 

 another occasion, a pathway straight through duckweed on the 

 small pond, showed that a muskrat had traversed there. 



Mus norweg'cus Erxleben. The large brown rat would also very 

 likely have been an inhabitant of burrows underneath overhanging 

 banks. It was reported (Stehle '20) as present, and the writer saw one 

 take to the water and disappear under the banks east of station 6, but 

 no trace of it could be subsequently found. 



