401 
1910-11.] Topography of Cerebral Cortex of Cuinea-pig. 
position of the motor, sensory, and undifferentiated areas, while the probable 
sites of the visual and fifth nerve centres are defined on the mesial surface. 
As a result of this work he draws the following conclusions : — 
1. The relative depth of the layers is of more value from the point 
of view of drawing conclusions than a consideration of the cortex as a 
whole. 
2. Regarded developmental^, ontogenetically, and phylogenetically, 
the facts adduced point to the mammalian cortex being built on an infra- 
granular basis. 
3. The supra-granular layer, corresponding to the pyramidal layer 
of Bolton, is practically absent in lower mammals. 
In this paper Watson points out certain peculiarities of the neopallium 
of the guinea-pig, such as the well-marked supra-granular layer. The cells 
in this layer, though numerous, are apparently mostly functionless, since 
they undergo little development after birth. 
Haller (40) gives an interesting paper on the phylogenetic relation- 
ship existing between the brains of various mammals. Three types — 
Chiroptera, Erinaceus, and Mustelidae — are fully described and compared. 
Mott and Halliburton (41) describe the cerebral localisation in the brain 
of the lemur. They localise the motor area in the central region of the 
cortex. 
Mott and Kelly (42) follow with a detailed description of the histological 
characteristics of the brain of the lemur. They describe the motor area 
as easily recognisable from histological appearances. 
Mott, Schuster, and Halliburton (43) give a detailed account of the 
cortical lamination and motor centres in the brain of the marmoset. 
They describe the motor areas as lying in the anterior half of the brain, 
and find, further, that a large portion of this area is associated with the 
movements of face, tongue, and mouth. This point is of interest, since 
the marmoset is dependent on the delicate play of those muscles for its 
insect prey. 
Bolton (44), in his chapter in Further Advances in Physiology, recapitu- 
lates much of what has already been published in his papers previously 
quoted (34, 35), and goes on to discuss the evolution of cerebral function, 
the work of Flechsig, Smith, Brodmann and others being referred to. 
Schuster (47) describes the cell lamination in the cerebrum of the 
Echidna in considerable detail, mapping out the whole cortex into some 
five different types of cellular arrangement. 
Schafer (46) describes a series of experiments made on monkeys, which 
show that the volitional impulses may pass from the cortex to the cord by 
vol. xxxi. 26 
