66 PYGATHRIX 
Measurements. Old male, total length, 1,430; tail, 810. Skull: 
greatest length, 104; zygomatic breadth, 80; Hensel, 73; intertemporal 
width, 46; interorbital width, 8; width of braincase, 69; median length 
of nasals, 12; palatal length, 34; length of upper molar series, 27 ; 
length of upper canines, 20. Collett, ex type. A skull of a female 
in British Museum measures somewhat less. Total length, 90.5; 
occipito-nasal length, 80.4; zygomatic breadth, 70; Hensel, 56; palatal 
length, 27. 
Mr. Collett gives the following account of this species, (1. c.): 
“These monkeys were only met with by Herr Iversen in the Langkai 
district and were not observed in Deli. They were fairly numerous 
on several of the estates, especially at Glen Bervie and Beckri. Their 
haunts were in the highest trees, and they never descended of their 
own accord to the ground, or visited the rice fields. Herr Iversen 
saw, however, one wounded individual take to flight on the ground. 
They always live in companies, and inhabit the dry spots in the 
thickest parts of the forests. They appear to be non-migratory, and 
may be met with at all times of the year in almost the same part of 
the forest. They hardly ever visited the more open places, but kept 
to the highest tree-tops, where they moved about with the greatest 
ease, and made the most astonishing leaps through the branches. They 
were, on the whole, excessively shy; if they found themselves dis- 
covered, they endeavored at once to hide, and the mothers would leave 
their young sitting on the branches whilst they themselves sought 
shelter in the tree-tops. When hunted they all took to flight in the 
same direction, so that the companies were not dispersed. 
“The companies appeared to consist chiefly of full-grown indi- 
viduals, and young ones were but seldom seen. An occasional half 
grown individual, however, might be noticed following the old ones; 
babies were not often seen, but these are, on the whole, more difficult 
to observe, as they are carried by the mother under her belly. The 
young one brought home was noticed through the mother deserting 
it, after which it began to shriek. They have a very penetrating cry, 
which they generally utter in chorus after one has given the note. In 
the individuals which have been examined no fcetus has ever been 
found. Possibly the pregnant females and the younger ones hide 
themselves more closely. 
“They were seen in activity only in the daytime, and were not 
heard to cry at night. They lived, it appeared, only on fruits. In 
their stomachs were chiefly found the soft pulp of a fruit, belonging 
