186 EDWARD L. RICE 
(fig. 28), the bone is everywhere separated from the septum by a 
considerable space, decreasing with the age of the embryo. In 
Emys this longitudinal ridge is well marked, according to Kunkel 
(12 b), and closely paralleled by a longitudinal rod of cartilage, 
the ‘pila supraglandularis.’ The latter structure is not found 
in Eumeces nor mentioned by Gaupp in Lacerta. 
In stage 5 of Eumeces the nasal septum is uninterrupted, 
although a thinner area in the region of the planum antorbitale 
suggests the anterior fenestra septi of Lacerta. In earlier stages 
not even this suggestion is present, while stage 6 shows an open- 
ing of considerable size. The significance of these observations 
has been discussed in connection with the interorbital part of 
the septum (p. 171). A similar, but very variable, perforation 
of the septum nasale is described in a number of turtles—Trionyx 
(Ogushi, 711), Emys (Kunkel, ’12 b), Chelonia and Dermochelys 
(Nick, ’12). In Chelydra Nick was unable to distingush a 
fenestra. This fenestration is probably wholly independent of 
the development of a fenestra (or thin spot) in the extreme 
anterior portion of the septum of various mammals, e.g., Echidna 
(Wilson, 700; Gaupp, ’08a), Ornithorhynchus (Wilson, ’00), 
Talpa (Fischer, ’01b), Sus (Mead, ’09), interpreted, after 
Spurgat (’96, cited by Mead), as correlated with the flexibility 
of the snout. 
Of the prenasal extension of the septum, described in Chelone 
(Parker, ’80; Nick, 712), Chelydra (Nick, 12), and Crocodilus 
(Gaupp, ’05b; Shiino, ’14), I find no suggestion in Eumeces. 
This structure is not mentioned by Gaupp in Lacerta and its 
presence in Dermochelys is denied by Nick. 
3. Roof of ethmoid region 
Owing to the need of external protection, the roof of the nasal 
capsule or tectum nasi (fig. 1) is very complete as compared with 
the very imperfect floor of this region. The two main nasal 
cavities, right and left, are domed over completely by a thin 
roof of cartilage except for the enormous fenestrae superiores 
nasi (figs. 1 and 27, fen.s.na.) already mentioned. In stage 6 
