272 PROCEEDINGS OF THE ACADEMY OF [1889. 



and they not infrequently extend for a considerable distance before 

 emerging from the ground. The runways as a rule, have their 

 exits upon the edge of some neighboring pond. Here the animal 

 finds the succulent grass upon which it feeds, and which grows 

 to a height of three or four feet in water half as deep. To procure 

 the best portions of the grass the Neofiber constructs a platform 

 of large sticks, upon which it sits and feeds at its leisure. The 

 largest platform observed measured ten by seven inches. In all my 

 many trips upon the water, by night, both with and without a light, 

 I never saw Neofiber swimming. It is probably, therefore, not much 

 given to nocturnal ramb lings. 



Mr. Chapman says of the habits of this animal: — "It is probable 

 that Neofiber is much less aquatic than the last-named species (the 

 common muskrat, Fiber zebethicus), a fact which would largely 

 account for the differences observed in their habits. That Neofiber 

 is quite at home in the water, however, was clearly shown by the 

 actions of a captured individual, which, placed in a tub of water, 

 swam and dived readily ; in swimming using the tail in a peculiar 

 gyratory manner, the tip describing circles." 



After the departure of Mr. Chapman from "Oak Lodge," I spent 

 four weeks in trapping this animal, and succeeded in catching two 

 specimens, one of which left me nothing but his foot as a remem- 

 brance of the occasion ; but the other was obtained alive and is now 

 in my private collection. This animal when caught and placed in 

 the bottom of my boat, made frequent attempts to escape by crawling 

 over the side. That he is not cowardly when in captivity was shown 

 by the ferocious manner in which he attacked my bare feet when I 

 chanced to come in his way. Mr. Chapman's statements regarding 

 the action of the tail in swimming were corroborated. I spent an entire 

 morning in studying the nests and in following out numerous runways. 

 One of these I found to extend for a distance of fifty feet and 

 to have its exit in a pond near by. The course of this runway some- 

 what resembled the curves of a snake when in motion. 



The description and measurements of the animal in my possession 

 are as follows : 



Neofiber alleni True. 



Above seal-brown ; below silvery-white, with a mixture of rufous ; 

 sides seal-brown, shading to a rufescent tinge, with here and there a 

 few silvery hairs scattered about; forehead and tip of nose black ; tail 

 of a rufescent tinge mixed with black. Adult male. 



