CHONDROCRANIUM OF EUMECES 167 
consideration will show that the contradiction is only apparent. 
The solution of the difficulty is suggested by a phrase of Kingsley 
(00), in which he characterizes the columella as developed “from 
the proximal end of the hyoid arch, or at least from the same 
continuous stroma.” In a similar way I believe that the colu- 
mella may be said to be developed from the otic capsule ‘‘orat 
least from the same continuous stroma.” It is not that the 
columella, or either of its halves, is a formal outgrowth from a 
previously developed otic capsule or hyoid arch; rather that 
otic capsule, columella auris, and hyoid arch are all parts of a 
‘continuous stroma’ of undifferentiated early embryonic tissue. 
In this, as suggested by Gaupp for another portion of the head 
skeleton (see also p. 180), the potentiality of cartilage develop- 
ment in situ is generally distributed. Thus the otostapes may 
develop in connection with the otic capsule and the hyostapes 
in connection with the hyoid arch, and yet hyostapes and oto- 
stapes may form a genetic unit in the columella auris. This 
unity is no more disturbed by the presence of somewhat distinct 
otostapedial and hyostapedial centers of chondrification than is 
the unity of the otic capsule itself by the fact that its chondrifi- 
cation does not proceed uniformly in all parts, but from rather 
distinct centers. On this interpretation the discussion of the 
otic or hyoid nature of the columella auris becomes like the classic 
dispute concerning the gold and silver shield. On one side the 
columella is of otic relationship, on the other it is of hyoid rela- 
tionship, but it does not thereby give up its unit character. 
This is not offered as a dogmatic statement of unquestioned. 
fact, but rather presented as the tentative result of the study of 
the development of the columella in Eumeces and an examination 
of the very confused and confusing literature dealing with the 
reptilian columella. 
JOURNAL OF MORPHOLOGY, VOL. 34, NO. 1 
