Foreword 
Dr. Paul D. MacLean began working with the squirrel monkey 
(Saimiri sciureus) in the Fulton laboratory at Yale in 1950, and intro- 
duced it into the NIMH laboratary in 1957. It has been an inspiration 
to observe the work he and his collaborators have done in the succeeding 
years. The squirrel monkey was first used in the United States by Hein- 
rich Kliiver. This gentle little primate from the South has continued to 
have increasing value for laboratory study. It is a small animal with a 
relatively large brain and a highly organized nervous system. It is quiet, 
trainable and adapts well to both acute and chronic experimentation. 
Large numbers can be contentedly maintained in a relatively small 
space. Resistance to infections, including tuberculosis, is high. 
Drs. Gergen and MacLean have produced this Horsley-Clarke type 
of atlas with meticulous care. It includes the whole hemispheres, and 
great effort has been expended to show the degree of scatter to be ex- 
pected. This atlas will be of great service to brain research. 
Bethesda, Maryland 
Wade H. Marshall, Chief, 
Laboratory of Neurophysiology 
