ANTHROPOMORPHIDA. 789 
wards, those of the forearm upwards ; except the plantigrade 
gibbons, the apes tend to walk on the edges of their feet ; 
there are no cheek-pouches ; there are no ischial callosities 
except in gibbons ; the ceecum has a vermiform appendix. 
The Gibbons (/Zy/odaées) live in §.-E. Asia, especially in the Malayan 
region. The largest attains a height of 3 ft. They walk erect with 
Fic. 418.—Skull of Orang-Utan. 
p., Parietal; /, frontal ; sg., squamosal ; 7., jugal ; 7z., maxilla. 
the hands reaching the ground. The skull is not prolonged into a 
vertical crest. There is an os centrale in the carpus. The hallux is 
well developed. The only flat nails are those of pollex and hallux. 
There are 13 ribs and 18 dorso-lumbar vertebre. ‘There are small 
ischial callosities,—the only instance in Anthropoids. They are mainly 
arboreal in their habits. They feed on fruits, leaves, shoots, eggs, 
