CHONDROCRANIUM OF EUMECES 183 
7. ETHMOID REGION 
1. General description 
The ethmoid region is very complicated and difficult to de- 
scribe. It is also a region peculiarly subject to secondary modi- 
fication in connection not only with the olfactory function, 
but also with the mechanical uses of the snout; moreover, 
as pointed out by Gaupp (06) and Kunkel (712 b), the 
structure of the ethmoid region is closely correlated with the 
function and structure of the jaws. It is presumably the type 
of jaw development which has determined the completeness , 
and solidity of the nasal capsule in crocodiles (Gaupp, ’05 b; 
Shiino, ’14) and turtles (Gaupp, 705 b; Ogushi, 711; Nick, 712; 
Kunkel, ’12b) and its incompleteness and delicacy in snakes 
(Gaupp, 705b; Peyer, 712). The lizards are intermediate be- 
tween these extremes. 
In the ethmoid region the formal differences between stage 5 
of Eumeces and Gaupp’s figures of Lacerta are very conspicuous. 
Some of these differences are reduced or disappear in a later 
stage of Eumeces; others, while conspicuous, are of little real 
significance; one, the more complete development of the lateral 
wall in the extraconchal portion of the capsule, seems constant 
in all stages and not without importance. 
In general, the ethmoid cartilages of Eumeces are of late devel- 
ment in comparison, for example, with those of the lateral tem- - 
poral wall. The latter, with the exception of the taenia mar- 
ginalis, are already in regression in stage 5; the former, with 
the exception of the nasal septum, are not yet fully developed. 
The dorsal view (fig. 1) is best adapted to general orientation. 
The main outline, disregarding fenestrae, may be compared to 
that of a heart, with the widely expanded atria turned toward 
the posterior, and the ventricles, slightly divergent at their tips, 
forming the end of the snout. The groove between the atrium 
and ventricle of each side is represented by the deep infolding 
of the aditus conchae (ad.co.), the auricle itself by the extra- 
conchal portion of the capsule (p.eat.). Posteriorly, between 
the two extraconchal portions, the roof of the nasal capsule ter- 
JOURNAL OF MORPHOLOGY, VOL. 34, NO. 1 
