CARNIVORA. 773 
3. Hystricomorpha.—Porcupines (Hystrix), agoutis (Dasyprocta), 
guinea-pigs (Cavza), and the S. American capybara (Hydro- 
cherus), the largest living Rodent, measuring about 4 ft. in 
length. 
4. Lagomorpha.—Hares and rabbits (Zefzs), and the picas or 
tailless hares (Lagomys), with incisors 2, 
_ In the first three sub-orders there is only a single pair of upper 
incisors, and the three may be united as Simplicidentata, in contrast 
with the Duplicidentata, where there are two pairs. Only in the Jatter 
does the enamel extend to the posterior surface of the incisors, which 
are also peculiar (in this order) in having well-developed milk pre- 
decessors. 
Fic. 416.—Skull of tiger, lateral view. 
px., Premaxilla ; #x., maxilla. Note the insertion of upper canine 
(c.1) just behind the suture line, and the fact that the lower 
canine (c.2) bites in front of it. 2a., Nasals; Za., lachrymal 
bone with foramen; /7., frontal; a., parietal; so., supra- 
occipital ; fa., paroccipital process; az., auditory aperture (the 
reference line crosses the inflated bulla) ; sg., zygomatic process 
of squamosal; @., angle of lower jaw; jz., jugal; ca., 
carnassial tooth of upper jaw; co., coronoid process of lower 
jaw. 
Order CARNIVORA 
This order includes lions and tigers, foxes and dogs, bears 
and otters, etc. 
Most of the Carnivora feed on animal food, and the most 
typical forms prey upon other animals and devour their 
