54 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XI. 



island in Rock River near Oregon, Ogle County, northwestern Illinois. 

 It has also been taken in the vicinity of Glen Ellyn, Du Page County, 

 Illinois, by Mr. B. T. Gault, who writes, "An Opossum was found 

 dead in our woods February 19, 1910, evidently having been killed 

 by dogs. It was quite badly mutilated and the fur slipped consid- 

 erably, probably having been dead some time. Another one was 

 killed here New Year's day and the man who did it tells me he has 

 taken two others within the past ten years." I have seen a specimen 

 killed near the Kankakee River not far from the Indiana line, and 

 another from the vicinity of Warsaw, Hancock County, Illinois. It is 

 also recorded by Dr. J. A. Allen from the latter locality (1. c., p. 162). 

 Farther south it becomes more common and is reported from various 

 places in southern Illinois. The Field Museum collection contains 

 specimens taken near Bogota, Jasper County, and Olive Branch, 

 Alexander County. 



The Opossum is very prolific; usually two and sometimes three 

 litters are born in a season and the young usually number from 8 to 13 

 in a litter. When born they are extremely small, considerably less than 

 an inch in length, imperfectly developed, naked and absolutely helpless. 

 They are immediately placed in the pouch by the mother, where they 



attach themselves to 

 the nipples and remain 

 so for several weeks 

 until sufficiently .grown 

 to be able to move 

 about and help them- 

 selves. When they are 

 able to leave the 

 pouch, they are often 

 carried about on the 

 back of the old Opos- 

 sum, clinging to her fur 

 and with their tails 

 wrapped around that 

 of their mother, which 

 she obligingly holds 

 over her back for the 

 purpose. 



Opossums are noc- 

 turnal in their habits, 



although I have occasionally met with one wandering about in the 

 woods in the day time. They move slowly when on the ground and 



