32 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. III. 



altogether too large array of witnesses to keep them from falling 

 back into the obscurity from which they have been mistakingly 

 brought. 



It is to be hoped, however, that the pendulum has reached the 

 farthest point in its swing towards an extreme radicalism in the 

 recognition of forms, and as it returns to a reasonable equipoise, that 

 a more conservative, and as it appears to many, a more sensible 

 treatment of the often insignificant differences in the appearance of 

 animals may be attained. 



ORDER MARSUPIALIA. 

 FAM. DIDELPHYID.E. 



DIDELPHYS. 

 Didelphys virginiana. 



Didelphys virginiana. Linn. Syst. Nat., i. 1758, p. 54. 



Didelphys pigra. Bangs, Proc. Bost. Soc. Nat. Hist., 1898, 

 p. 172. 



Six specimens from New Berlin, Anastasia Island, Enterprise, 

 and Gainesville, Florida. 



These examples ought to belong to the race named pigra by 

 Mr. Bangs, but I fail utterly to discover any character to dis- 

 tinguish them from typical D. virginiana. Mr. Bangs states 

 (1. c.) that pigra is "smaller" than the Virginia opossum, with a 

 "longer and more slender tail and smaller feet." All these 

 are comparative distinctions and may be observed among indi- 

 viduals in any series of opossums from various localities, 

 occasionally even from the same locality. In size these six 

 specimens range in their total length from 712 to 890 mm., and 

 the tails from 300 to 370. It will thus be seen that within these 

 figures are practically embraced the measurements of the Vir- 

 ginia opossum, which ranges, in my experience, from 570 to 871 

 in total length and the tail from 260 to 394, therefore the average 

 Florida animal does not seem to be smaller than the typical 

 form, but the tail may be slightly longer. If this is a character, 

 however, it demands an absolute certainty of locality and a 

 considerable number of examples to prove as to which form a 

 specimen may belong, two desiderata not always possible to 

 command. Of twelve specimens of D. virginiana, in the New 

 York Museum of Natural History, the measurements of which 

 were kindly sent to me by Dr. Allen, the following figures repre- 



