78 ARKIV FÖR ZOOLOGI. BAND 14. NIO 4. 



The from Didelphyidae independent origin as deduced 

 from the structure of the feet is supported by several other 

 facts as well and also by the following observations on the 

 structure of the tail of Caenolestes. 



Thomas has said^ that the terminal inch of the tail 

 below is wholly naked, and he draws from this the conclu- 

 sion, that this organ is »presumably prehensile». I have not 

 been able to observe anything like that on my specimens. 

 As already stated above, the tail of C. fuUginostis is deci- 

 dedly more hairy along the lower, than on the upper side. 

 In G. ohscurus the tail is all över more scantily hairy than 

 in the former species, but just towards the tip it is some> 

 what more hairy below than above, and some longer hairs 

 extend beyond the tip of the tail from the lower side. It 

 is also to be observed that in both the alcoholic specimens 

 of C. ohscurus the tip of the tail is curved somewhat up- 

 wards. This appears to contradict that it should be pre- 

 hensile in a downward direction as usual in Marsupials. On 

 the contrary it rather indicates a faculty of curving the tail 

 in a dorsal or upward direction round some object. An exa- 

 mination of the terminal portion of the tail of alcoholic oh- 

 scwn^5-specimens reveals, that the extreme point of the same 

 is naked and looks soft and tactile, but there is no quite 

 naked area extending forwards from this point, neither on 

 the upper, nor on the lower side, but the upper is evidently 

 more flattened, w^hile the ventral side is more rounded (part 

 of a cylinder) and, as already mentioned, really more hairy 

 than the upper. Having stated this, I turned to the dry 

 o&5Ci^rw5-specimen, which, although immature, is not so young 

 as the alcoholic ones and found that on the upper side of 

 the tail even the scanty hairs were absent along a strip 

 perhaps extending 8 mm from the tip. In the three dry 

 specimens of C. fuliginosus such a naked strip on the upper 

 side of the tip of the tail is still more pronounced and more 

 conspicuous in consequence of the more developed general 

 hairiness of the tail in that species. Without doubt it is 

 this naked strip on the upper side of the tail, which Tho- 

 mas has seen, but as the thin tails of preserved small mam- 

 mals unfortunately often get twisted round, he has got the 

 impression, that it was situated on the lower side, as is the 



1 Proc. Zool. Soc. 1895, p. 872. 



