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Butler 
Figure 1. Photomicrographs of Nissl stained cross sections through the telencephalons of the lizards 
Gekko gecko (shown on the left) and Iguana iguana. Note the prominant corticoid band surrounding a core 
nucleus in the dorsal ventricular ridge of Gekko, as opposed to the presence of a number of nuclear 
groups and the absence of a definitive corticoid band in the DVR of Iguana. 
AC = Anterior commissure; CP = Cell plate of dorsal cortex (Unger, ’06) ; DCl = Dorsal cortex pars 
lateralis; DCm = Dorsal cortex pars medialis; DVR = Dorsal ventricular ridge; DVRc = Core nucleus 
of dorsal ventricular ridge; DVRs = Surrounding corticoid band of dorsal ventricular ridge; HC = Hip- 
pocampal commissure; LCd = Lateral cortex pars dorsalis; LCv = Lateral cortex pars ventralis; MC 
= Medial cortex; S = Septum; ST = Striatum; V= Lateral ventricle. 
the basis of cell packing density. A number 
of cell types have been identified in the 
lateral cortex of various reptilian species, in- 
cluding fusiform (Northcutt 1967, 1970; 
Voneida and Ebbesson, 1969), double pyra- 
midal (Northcutt, 1970; Ulinski, 1974), and 
polygonal, multipolar, and stellate (North- 
cutt, 1977, 1970; Voneida and Ebbesson, 
1969; Ulinski, 1974), 
Medial wall. The medial wall is composed 
of two cortices, a small-celled medial cortex 
(MC) and a large-celled dorsomedial cortex 
(DMC). Northcutt (1967) described goblet, 
double pyramid, and small intrinsic cells in 
these cortices (his hippocampus pars dorso- 
medialis and hippocampus pars dorsalis) in 
Iguana. Ebbesson and Voneida (1969) found 
a similar variety of cells in Tupinambis, and 
Ulinski (1974) described candelabra cells in 
the medial cortex and a variety of cell types, 
including double pyramids, in the dorso- 
medial cortex in snakes. The medial wall of 
the telencephalon in turtles (Northcutt, 
1970) also contains similar cell types, but the 
double pyramids in the dorsomedial cortex 
do not form the distinct layer seen in lizards. 
Dorsal wall. The dorsal cortical area is 
usually divided into medial and lateral parts. 
The medial part of dorsal cortex (DCm) lies 
ventral to the cells of dorsomedial cortex, 
and the lateral part (DCl) lies medial to 
the dorsal part of lateral cortex. Addition- 
ally, Unger (1906), has identified a ventral 
cell plate which is particularly well developed 
in Gekko and is formed by clumps of cells 
similar to those that form the corticoid band 
in the dorsal ventricular ridge. Unger noted 
that this ventral cell plate corresponds to 
the corticoid band, and the continuity of 
these two structures can be seen in some 
sections. 
A variety of cell types have been described 
in the dorsal cortex of reptiles, of which 
relatively large multipolar or double pyra- 
midal cells with either spiny or nonspiny 
dendrites appear to be most common 
(Northcutt, 1967, 1970; Ebbesson and 
Voneida, 1969 ; Ulinski, 1974). 
Dorsal ventricular ridge. The dorsal ven- 
tricular ridge (DVR) shows the most obvi- 
ous interspecies differences in morphology. 
In lizards such as Gekko, the ridge is com- 
prised of a core nucleus (DVR) surrounded 
by a corticoid band of clumped cells (DVRs) ; 
