TWO TYPES OF MONKEYS 
All the gibbons are peaceable among themselves, gentle, 
cheerful, easily tamed when caught young, and show a quick 
affection toward man. One of the most complete and illumi- 
nating studies of the group is that by Haeckel.?8 
Baboons, Monkeys, and Marmosets 
It has already been said that all the Primates fall into one of 
two groups: (1) the broad-nostriled or Old World apes and 
Monkey monkeys; and 
Jppes: (2) the New World, i i 
? /I Ws 
narrow - nostriled monkeys uf, 2) 
and marmosets. A part of . wa), YZ 
the former group (man and \2 = Zy 
the manlike apes) have been 
considered. Now we are to 
take up the remaining fam- 
ilies of Primates, only three 
in number, which comprise 
the baboons, macaques, langurs, capuchins, howlers, marmosets, 
and others popularly recognized as ‘‘monkeys.”’ 
TYPES OF NOSTRILS IN MONKEYS, 
1. Platyrrhine. 2. Catarrhine. 
One of the most singular and interesting things in zodlogy is the deeply 
cut line separating these two groups of animals, which at first glance seem 
so much alike. The compressed noses of the Old World apes and monkeys, 
to which they owe their group name Catarrhina, contrasted with the widely 
separated, outward-flaring nostrils of the Platyrrhina, or New World fami- 
lies, give only one of several distinctions. The former are, as a whole, of 
larger size than the latter. Their anatomy differs; thus while the catar- 
rhines (including man) have only thirty-two teeth, the platyrrhines have. 
thirty-six — four extra premolars. The catarrhines generally have those 
patches of hard, hairless, brightly colored skin on the buttocks, termed 
ischial callosities, never present in the American forms, for the latter 
do not sit up upon their haunches. Some Old World monkeys boast 
long tails, but these never show the slightest tendency toward that pre- 
hensibility so characteristic of our platyrrhines. Again, no American 
monkey possesses distensible folds inside of the cheeks, called cheek 
23 
