CHONDROCRANIUM OF EUMECES 149 
interruptions of the cartilage are apparently present in the 
bottom of the fossa subarcuata (fig. 1). The character of the 
filling tissue is very problematical; it was first interpreted as 
cartilage, later as procartilage. Hence the difference in figures 
1 and 8, drawn from two different models based upon the same 
series of sections. On one side there are two such openings, 
leading, respectively, into the cavum vestibulare anterius and 
cavum vestibulare posterius; on the other side the opening into 
the cavum anterius cannot be recognized. The filling of all 
three in stage 6 is unquestionably cartilaginous. 
Fenestra vestibuli (fig. 7, fen.vest.). The fenestra vestibuli is 
decidedly elongated parallel to the prominentia cochlearis (dorso- 
posterior to ventroanterior), and slightly larger, at least in stages 
5 and 6, than the footplate of the columella auris which rests 
in it. In Lacerta the fenestra is circular; in Emys (Kunkel, 
12 b) itistriangular. In earlier stages of Eumeces the cartilages 
of footplate and cochlear wall are seemingly continuous, thus 
obliterating any distinct fenestra vestibuli (see also p. 163). The 
position with reference to the entire otic capsule is essentially 
the same in Eumeces and Lacerta, although the enlargement of 
the cochlea gives it the appearance of being much more dorsal 
in Kumeces. 
Fenestra cochleae and fissura metotica (figs. 2, 7, and 8, fen.coch. 
and fis.m-ot.). The relation of the fenestra cochleae to the 
fissura metotica is so intimate that the two may be advantage- 
ously discussed together. As already noted, the fissura metotica 
is terminated dorsoposteriorly much sooner in Eumeces than in 
Lacerta by a sudden flaring of the occipital arch and its union 
with the prominence of the posterior semicircular canal. The 
examination and modeling of earlier and later stages of Eumeces, 
stages 2 and 6, fully confirm this fusion. In Lacerta the dorsal 
extension of the fissure is without essential significance, being 
filled with connective tissue and containing neither nerves nor 
important blood-vessels. Gaupp (’00, p. 445) also describes an 
individual variation in which the fissure is almost completely 
obliterated above the dorsolateral angle of the foramen magnum, 
