a. B of Ateles - Squ-Wstl Callicebus 
b. W of Saguinus - W of Leontideus 
t. ^ 
% YiVS 
V. The ritualized postures and movements of different species are more varied, 
in basic structure, than their vocal patterns. Some species have relatively few 
ritualized postures and movements. This seems to be the primitive condition in the 
family, 
The patterns which seem to be possessed by all or almost all species are the 
following: 
1. BT. 
2. Lsh. 
J. LB or Hdd. 
4. Some form of Set. 
Several of the more specialized groups have developed much more elaborate repertories 
of display movements and postures. Almost certainly evolved independently. 
Hiis elaboration has proceeded along two lines: 
1. Facial expressions Cebus . Ateles . Caca.iao . 
2. Movements of body and limbs, plus erection of hair tufts — — marmosets, especially 
Cebuella. 
VI. Individuals of a few species (Cebus spp, and, possibly, Caca.iao rubicundus ) 
show a very marked tendency to learn to perform unusual and distinctive movements in 
certain abnormal conditions of captivity. Different individuals of the same species may 
learn very different patterns in similar circumstances. Such distinctive patterns may 
also function as signals, even when they are very different from any species-specific 
patterns • ^/hen individuals who have learned to perform such distinctive patterns are kept 
in a group with other individuals of their own species, the latter quickly learn to 
recognize the significance of the distinctive patterns, and respond appropriately# The 
