1909.] Cortical Lamination, etc., in Brain of Marmoset. 



133 



where the ear area is a large and important one. No experiments of the 

 nature of extirpation were carried out. 



Summary. 



1. The brain of the Marmoset is small and broken by comparatively few 

 fissures, and of these only the Sylvian, hippocampal, and calcarine fissures 

 show any considerable depth. 



2. A series of sections of the cerebral cortex were made to map out the 

 boundaries and characters of the types of cell-lamination which occur. The 

 result of this work is given in the accompanying diagrams, and some of the 

 principal types are illustrated in the plates. 



3. As was found in the Lemur, the motor area consists of two types ; 

 in one of these (motor area A) the Betz cells are large and conspicuous ; in 

 the other (motor area B), which corresponds to face and head movements, 

 not only are the motor cells smaller, but a layer of granules indicates that 

 this part of the brain is sensori-motor in function. 



4. By stimulation, the boundaries of the excitable cortex were found to 

 coincide with those mapped out by histological examination. The sequence 

 from below upwards of head, upper limb, and lower limb is that which 

 usually prevails in mammals. 



5. Although no movements of the eye were obtainable by stimulating the 

 occipital pole, this is to be attributed to the difficulty of the experiment. 

 Histological examination of this region shows it to possess the structural 

 characters of the visual cortex in other animals. 



6. The other portions of the cortex, which are described in full in the 

 text, call for no special comment. They do not differ in any marked 

 character from those previously described in corresponding regions in related 

 animals. 



[Additional Note. — The cortex of the Marmoset (Hapale) has been mapped 

 out in great detail by K. Brodmann* in a work which has come to our 

 notice only since the completion of our paper. 



As this work is rather in the nature of a general summary of the subject 

 of cortical lamination, no special descriptions or figures are given of the 

 numerous types of cell lamination to which he refers. To what extent 

 his results correspond with our own may be seen by a comparison of 

 our fig. 1 with his figs. 96 and 97 (p. 161). It will be noticed that 

 there is a very close agreement with regard to the extent of the visual 



* Dr. K. Brodmann, ' Vergleichende Lokalisationslehre der Grosshirnrinde,' Leipzig, 

 1909. 



