188 EDWARD L. RICE 
4. Lateral wall of ethmoid region 
The most striking characteristic of the paries nasi or lateral 
wall of the ethmoid region in stage 5 of Eumeces (fig. 3) is its 
imperfection as compared with that of Lacerta. In the anterior 
third, especially, the paries is reduced to a narrow margin of the 
tectum, slightly deflected ventrally. On this deflected margin 
two projecting lobes may be distinguished—the processus alaris 
inferior (pr.al.z.), at the tip of the snout, and the processus alaris 
superior (pr.al.s.), a little further posterior, or rather dorsal 
because of the downward bend of the snout. In the notch be- 
tween these two processes is located the external nostril. The 
processus alaris superior is far less prominent than in Gaupp’s 
figures and model of Lacerta; in Crocodilus (Shiino, 714) and 
Emys (Kunkel, 712 b) there are no alar processes; in Vipera 
(Peyer, 712) they are well developed. 
Between the anterior and middle thirds of the ethmoid region 
the paries is notched out rather strongly, just posterior to the 
superior alar process, broadening again immediately in a pro- 
jecting lobe which occupies the entire middle third. Here, 
more than elsewhere, the lateral wall approaches the solum nasi, 
but, in this stage, it is very far from the fusion in Lacerta, on the 
strength of which Gaupp names a ‘zona annularis,’ in which the 
nasal cavity is surrounded by a complete ring or tube of cartilage. 
The contrast here is due mainly to late chondrification in Eu- 
‘ meces; in stage 6 the union is complete, although the connecting 
cartilage is still histologically very young. In fact, this con- 
nection is already suggested in stage 5 by a condensation of the 
embryonic connective tissue, which, however, hardly deserves 
the name of procartilage. In the earlier stages there is not even 
this suggestion of the union. Even in stage 6 of Eumeces the 
term zona annularis is hardly justified, for, just where the lateral 
wall and solum are united, the tectum is largely obliterated by 
the exceptionally large fenestra superior nasi (fig. 27). The 
contrast with Lacerta is, however, one of degree, not of kind. 
The presence of the zona annularis in Lacerta is confirmed by . 
Beecker (’03), who describes a similar structure in Platydactylus. 
It is conspicuously developed in the turtles (Nick, 712; Kunkel, 
