CHONDROCRANIUM OF EUMECES 191 
and even in some lizards (Born, ’79, who mentions Scincus, 
Gongylus, Lygosoma, Eumeces, Euprepes, Marethia, Hinulia, 
and Hemidactylus); more recently its absence has been con- 
firmed in the crocodile (Shiino, ’14) and reported in Platydactylus 
(Beecker, ’03), Vipera (Peyer, ’12), Dermochelys, Chelone, and 
Chelydra (Nick, 712), and Emys (Kunkel, ’12b). The fre- 
quency of its absence in the reptilian series suggests the possi- 
bility that the fenestra lateralis of Lacerta may be nothing more 
than another area of retarded chondrification like those described 
in the otic capsule of Lacerta, Emys, and Eumeces—a, possi- 
bility which gains in significance from the absence of the fenestra 
in mammalian embryos—mole (Fischer, ’01 b), Echidna (Gaupp, 
08 a), pig (Mead, ’09), rabbit (Voit, ’09 b), dog (Olmstead, ’11). 
Another explanation is suggested by the conditions in Spheno-. 
don. The fenestra lateralis is not recorded by Schauinsland 
(00); but, according to Howes and Swinnerton (’01), it makes 
its appearance in very late embryos. It has also been found in 
the adult skull of Trionyx by Ogushi (11), although lacking, 
as noted above, in embryos of other turtles and even in the newly 
hatched young studied by Nick (12). A precocious develop- 
ment of the fenestra in Lacerta and a retardation in the other 
forms might well explain the strikingly contradictory conditions. 
Only a further investigation, particularly of late embryos and 
adults, can determine the history of the fenestra lateralis and the 
question of its significance or non-significance. 
Just posterior to the concha, the free ventral and posterior 
margins of the paries nasi meet in an angle of about 90°, marking 
the point of its greatest extension (fig. 3, p.tr.). This is clearly 
the equivalent of the more extensive pars triangularis of Lacerta. 
Near this, but connected in stage 5 only by a mass of procarti- 
lage or condensed connective tissue, is an isolated and rather 
irregular cartilage element (figs. 2 and 3, pr.max.a. and pr.max.p.), 
to be homologized with the maxillary processes, anterior and 
posterior, of Lacerta. In stage 6 this mass is continuous with 
the nasal capsule, as in Lacerta, while in the earlier stages the 
separation is even greater than in stage 5. In stage 5 it is pos- 
sible to distinguish a rudimentary anterior process (pr.maz.a.) 
