CHONDROCRANIUM OF EUMECES 8) ari 
form a processus paroticus. For the turtles the data are diver- 
gent. In Emys Kunkel (712 b) notes that no separate processus 
paroticus is present, and the occurrence of a processus dorsalis 
in Testudo is denied by Bender (12, correcting an error in his 
paper of 1911, in which the foot plate of the columella was men- 
tioned under this name). Parker (’80), however, records its 
presence in Chelone; and in a late stage of Chelydra Nick (’12) 
notes that the end of the ossified crista parotica, in contact with 
the quadrate, remains cartilaginous. This may perhaps be a 
remnant of the processus paroticus. 
Versluys (’98) has given a generalized description and figure 
of the lizard columella auris, to which Lacerta conforms in 
extraordinary detail; the agreement of Eumeces is less complete. 
For convenience of description, the columella may be divided into 
three parts—a footplate, fitting into the fenestra vestibuli; an 
insertion plate, connected with the tympanic membrane, and a 
rather slender stalk, connecting the footplate and insertion plate. 
It is further convenient to distinguish as stapes the proximal 
portion of the columella, and to apply the name extracolumella 
to the distal portion. In adult reptiles the stapes ossifies, while 
the extracolumella remains cartilaginous; thus the distinction 
is very clear. On the other hand, the junction may be optically 
unrecognizable in the cartilage of the embryo, as is the case in 
my specimens of Eumeces. It is located in the stalk, just proxi- 
mal to the processus dorsalis and processus internus described 
below. In the naming of processes of the columella, I follow 
the usage of Versluys, adopted also by Gaupp. In the following 
formal comparison with Lacerta, the description applies to 
stage 5 of Eumeces unless otherwise specified. 
The fenestra vestibuli and footplate of the columella in Eu- 
meces are not circular, as in Lacerta, but strongly elliptical, the 
long axis extending from posterodorsal to anteroventral. The 
fenestra is decidedly larger than the footplate, leaving a consider- 
able space, especially at the ends, which is filled with non- 
cartilaginous tissue. Of the ‘double fenestral structure’ and the 
‘stapes inferior’ described by Kunkel (’12 a) in Emys I find no 
suggestion. The stalk, instead of being attached at the middle 
