L 1*3 ] 



No. XXVII. 



Supplement to the account of the D/'pus Amcricanus, in the IV. 

 Vol. of the Transactions of the Society. See No. XII. 



Read Dec. 16th, 1803. 



IN the 4th volume of the Transactions of the American 

 Philosophical Society, I have given an account of a new 

 species of Dipus, or Jerboa. When that paper was presented 

 to the society, I was not able to say, with absolute confidence, 

 though I thought it highly probable, that the animal which I 

 described was one of the lethargic species of Glires, or those 

 species which pass the winter-season in a torpid state. I have 

 now completely satisfied myself, that the Dipus Americanus 

 does go into the torpid state, in the neighbourhood of Phila- 

 delphia. 



In the month of August, 1796, one of these little animals 

 was brought to me from the vicinity of this city. It was put 

 into a large glass jar, where I was so fortunate as to preserve 

 it for near four months. Though it made many efforts to 

 escape from its confinement, it seemed, upon the whole, pretty 

 well reconciled to it. It continued active, and both ate and 

 drank abundantly. I fed it upon bread, the grain of Indian 

 corn (Zea Mays), and the berries of the Prinos verticillatus, 

 sometimes called black-alder. 



On or about the 22d, of November, it passed into the tor- 

 pid state. It is curious to observe, that at the time it became 

 torpid, the weather was unusually mild for the season of the 

 year, and moreover the animal was kept in a warm room, in 

 which there was a large fire the greater part of the day and 

 night. I sometimes roused it from its torpid state; at other 

 times it came spontaneously out of it. During the intervals 

 of its waking, it both ate and drank. It was frequently most 

 active, while the weather was extremely cold in December: 

 but when I placed the jar upon a thick cake of ice, in the 



