676 PROCEEDINGS OF THE NATIONAL MUSEUM. vou. xxxtv. 
PONGO ABELII (Clarke). 
1826. Simia abelii CLARKE, Asiatic Researches, XIV, 1826, p. 489. 
1904. Pongo pygmaeus bicolor, RoTHSCHILD, Proc. Zool. Soc. London, 1904, 
IT, p. 489. 
1905. Simia swmatrana deliensis, SCHNEIDER, Zool. Jahrb. Syst., XXIII, p. 39. 
Seventeen specimens, skins, skulls, skeletons, and brains, from the 
vicinity of Aru Bay. Both sexes and many different ages of each are 
represented in the series. For list of these specimens and measure- 
ments see table, page 678. An examination of this material convinces 
me that not more than one species is represented among them. Taken 
as a whole the series of skulls shows a considerable amount of vari- 
ation. Differences in age and in sex among Orang skulls produce 
great variations in size and in shape. Even when these factors are 
eliminated and comparisons are made between skulls of like age and 
sex, considerable individual variation is found to be present, but there 
are always certain specimens connecting the extremes. In the general 
region visited by Doctor Abbott, Selenka,* however, recognized two 
subspecies of the Orang and Doctor Abbott in his field catalogue 
designated some of his specimens as “large species” and others as 
“small species.” So far as the material I have examined shows these 
differences may be accounted for by differences in age or in the de- 
velopment of cheek callosities. From an examination of the pre- 
pared skins it is no easy matter to determine to the degree of develop- 
ment of the cheek callosities. The appearance of a freshly lalled old 
male is shown in Plates LV and LVI. 
The color of the skins of this series varies from a dark chocolate 
to tawny or even ochraceous. The predominating color ranges from 
chestnut to cinnamon-rufous. None of the specimens are uniform in 
color throughout, the sides, chest, and limbs being clothed with 
darker hair than the top of the head, middle of back, or abdomen. 
The beard is always light in color, about ochraceous. The skin of the 
face is blackish as well as that of the hands and feet. The face has a 
thin sprinkling of short ochraceous hairs. 
In adult males the beard is about 100 mm. in length at the point, 
in females and in immature males it is much shorter, 50 mm. or less. 
On the sides of the back and around the thighs the hair is very long, 
reaching a length of 375 mm. in the full grown males. It is usually 
much less in the females and in immature individuals. On the breast 
the hair may be thick or scant, reaching a maximum length of about 
180 mm. On the top of the head and middle of back the hair is rela- 
tively short. The long, coarse, shaggy nature of the hair is well seen 
in Plate LY. 
® Sitzb. k. p. Akad. Wissensch., Berlin, 1906, p. 389. 
