72 ARKIV FÖR ZOOLOGI. BAND 14. NIO 4. 



I. |; C. J; P. I; M. ^. It is unknown to me, what has brought 

 about this change, but the present material gives me the 

 opportunity of stating, that the by Thomas first written 

 formula is the correct one. In a young male of C. obscvrus, 

 in which the liindmost small molar of the upper jaw has 

 not yet appeared, it can be plainly seen, that the tooth in 

 front of the three big molariform ones is still in the process 

 of growing up. Laterally its cingulum is just appearing at 

 the alveolar margin, but on the inner side it has not yet 

 come up to the level of the palatal surface. This cannot be 

 interpreted in any other way than that this tooth is growing 

 up and succeeding another, which has been displaced. The 

 new tooth must thus be the hindmost premolar, and all teeth 

 behind the same true molars, the number of which thus is 

 four. The same thing can be seen still more plainly on the 

 lower jaw. In the same the hindmost small molar is already 

 fully developed, and in front of the same the three large 

 molariform teeth are seen. In front of these latter again 

 the tip of a tooth is just appearing above the alveole, or 

 just cutting the gum. It is thus quite clear that this is 

 the new hindmost premolar, which is on its way having dis- 

 placed a predecessor, and behind the same there are conse- 

 quently four true molars in the lower jaw as well. 



Caeiiolestes obscurus Thomas. 



1 c? subadult; ^i/g 1914, on the road to Gualea 1 c? 1 ? 

 in alcohol ^Vg 1919 & ^^/^ 1920; near La Carohna 3 miles N. 

 of Quito, altitude 9,400 feet. 



This dry specimen is different from those described above 

 as C. fuliginosus as well with regard to its colour etc. as 

 with regard to its skull and dentition. It is much darker 

 above and less brown. The colour of the back is somewhat 

 resembling Ridgway's (1912) »fuscous», but darker and more 

 brownish, but is still more similar to Oberthur's & Dauthe- 

 nay's darkest shade of ^^warm sepia» (Rép. d. Coul. 305, 4). 

 On the flanks some grey is mixed in, and the lower parts 

 are strongly overlaid with long greyish white tips to the 

 hairs. 



The tail is as dark below as above, and the hairs are 

 short and sparsely set everywhere, so that the scales can 



