CLASS i ORDER Ly. 57 
inferior 8, the two middle ones broader and very 
short; canine teeth long ; grinders denticulated $ 
tongue ciliated with papilla ; teats (in most spe- 
cies) contained in an abdominal pouch. 
Macrovus, (kangureo,) front teeth in upper 
jaw 6, (in young ones 8,) emarginated ; in lower 
jaws 2, very large, long, sharp, and pointed for- 
ward ; grinders. 5 on each side, both in upper 
and lower jaw, distant from the other teeth ; fore 
legs very short; hind legs very long; the female 
haying an abdominal pouch. 
ORDER 4. ARROSORES. 
Having incisors tn beth jaws and no euspidate 
s Z P 
teeth ; toes with nails ; feeding almost wholly on 
vegetable substances. They are the proper gnaw- 
ers. 
Castor, (beaver,) incisors in the upper jaw 
iruncated and excavated with a transverse angle ; 
in the lower jaw transverse at the tips ; grinders 
on each side 43 tail long, depressed and scaly ; 
has collar Lidiies. 
Mus, (rat, mouse,) upper incisors wedge-form ; 
_ grinders 3 on each side, rarely 25; having collar 
bones. 
Myoxus, (dormouse,) incisors 2, upper wedge- 
form, lower ee. aes grinders 4 in each jaw; 
vibrissz long ; tail cylindric, villose, thicker to- 
wards the end ; legs of equal ALS 4 toes to 
each fore foot. 
Divus, (long-foot mouse,) incisors 2 above oe 
2 below ; fore legs very short, hind legs very long 
having collar bones. 
Arcromys, (rat-bear,) incisors.2 in each jaw, 
strong, sharp, wedge-form 3 grinders in upper jaw 
