7) 
8) 
25 
lum cornu ammonis (sub), extend into the molecular layer 
of the general cortex and at the junction of alveus (alv) and 
corona radiata (cr) there appears to be a slight intermingling 
(and possible interchange) of fibres from the corona radiata, al- 
veus and stratum lacunosum. 
At the mesial edge of the corona radiata the most marginal 
bundles of the longitudinal association fibres of the general cor- 
tex are plainly visible and constitute the cingulum (cing). 
These fibres are intermingled with longitudinal bundles of the 
adjacent alveus. 
The gyrus fornicatus (gyr. for) is the direct continuation of the 
gyrus hippocampi. 
Fig. 1. 
The transition or Early Eutherian type (Fig. 2). 
This is to be found in many Edentata and Cheiroptera and pro- 
bably in other orders. 
The main features of the scheme are readily recognisable by com- 
parison with figure 1. 
1) 
2) 
The following features are to be specially noted: — 
The size of the hippocampus has become greatly reduced. 
The “commissura dorsalis” is now not purely hippocam- 
pal (as in figure 1) but contains fibres which spring from the 
general cortex bordering upon the hippocampus. These new 
fibres pass through the alveus (alv). 
