188 ON THE ANATOMY OF THE KOALA. 



loped caecum and caecum-like ascending colon, with their longitudinal 

 folds of mucous membrane ; and the absence of an azygos lobe to the 

 lungs, the Wombats agreeing with the Phalangers in possessing one. 

 Hence it appears to me to be a more natural course to keep these three 

 groups together as subdivisions of a larger one, though whether that one 

 be called a family, or made into a larger section, will depend on the value 

 attached to those ideas by different naturalists. Adopting the former 

 as most convenient, they might be defined briefly as follows : 



PHALANGISTID M . 



Diprotodont Marsupialia, with clavicles, and not more than six 

 incisors above. The hallux present ; the 2nd and 3rd digits of the pes 

 smaller than the others, and more or less united together by integument. 

 Stomach not sacculated. Caecum present. Grlans penis more or less 

 bilobed ; vaginas provided with median culs-de-sac which may unite. 



1. 



Teeth rooted ; superior incisors 3.3; at least one small additional 

 preinolar on each side above. Tail well developed. No cheek-pouches. 

 Stomach and ascending colon simple. Caecum long, simple. Liver not 

 complicated by secondary sulci, and with distinct caudate and Spigelian 

 lobes. Lungs with an azygos lobe. Vaginal culs-de-sac coalesced (at 

 least in Phalangista). 



Phalangista, Cuscus, Belideus *, Acrobata *, Dromicia *. 



P. Z. S. 1881 , 2. PHASCOLAECTIN^E. 



Teeth rooted ; superior incisors 3.3; additional premolars absent. 

 Tail rudimentary. Distinct cheek-pouches. Stomach with a cardiac 

 gland. Caacum very long; commencing colon caecum-like, both being 

 dilated and provided with numerous longitudinal folds of mucous mem- 

 brane. Liver very much complicated by secondary eulci ; caudate lobe 

 not free; gall-bladder immensely elongated. Lungs with no azygos 

 lobe. Vaginal culs-de-sac free. 



Phascolarctos. 



3. PHASCOLOMYIM. 



All teeth rootless ; superior incisors 1.1; no additional premolars. 

 Tail and cheek-pouches rudimentary. Stomach as in Phascolarctince. 

 Caecum short, peculiar. Commencing colon transversely sacculated. 

 Liver somewhat complicated by secondary sulci; no distinct caudate 

 lobe. Lungs with an azygos lobe. Vaginal culs-de-sac free. 



Phascolomys. 



* For an opportunity of dissecting examples of these genera I am indebted to the 

 liberality of our President. 



