407 
1910 — 11 .] Topography of Cerebral Cortex of Guinea-pig. 
if Watson’s view be accepted — that they are not at least wholly sensory. 
Arguing from these facts, it would seem that these large pyramidal cells are 
associated with outgoing volitional impulses. They merge into the next 
zone. 
6. A wide zone of polymorphic cells. These three zones correspond to 
Bolton’s sub-granular zone. 
(See fig. 4.) 
Type III. (# # •) below and in front of Type II. 
Depth of cortex 1*5 mm. varying to T4 mm. 
1. Zone I. 
2. A zone of small angular and pyramidal cells. 
3. A broad granular zone. 
4. A zone of pyramidal shaped cells, some of which are 30 jj, long and 
12 to 15 fx broad, but these larger cells are not nearly so abundant as in 
Type II. 
5. A broad zone of polymorphic cells. 
. (See fig. 5.) 
Type IV. (® ® ®) in front of Type III. 
Depth of cortex 1*3 to 1*2 mm. 
1. Zone I. 
2. A zone of small angular and pyramidal cells. 
3. A broad, well-marked granular zone. 
4. A zone composed of granular cells interspersed with pyramidal cells. 
5. A broad polymorphic zone, the basis of which seems to be largely 
composed of small, almost granular, cells. 
(See fig. 6.) 
Type V. (o o o) a t Ihe anterior pole. 
Depth of cortex 12 to 1 mm. 
1. Zone I. 
2. A broad zone of polygonal cells interspersed with a few pyramidal cells. 
3. A well-defined granular zone. 
4. A broad, clearly defined zone of angular cells, among which are a 
very few small pyramidal cells. 
5. A broad zone of very small polymorphic cells. 
(See fig. 7.) 
