400 PROF. HUXLEY ON THE REPRESENTATIVES OF [May 27, 
Such developmental evidence as exists is entirely in accordance 
with the view of which these anatomical facts appear to me to afford 
a sufficient demonstration. 
Rathke distinctly states that in Coluber natrix the stipes results 
from a modification of the upper end of the hyoidean arch. Prof. 
Peters does not allude to this important circumstance; and, what is 
still more remarkable, in giving an account of his observations on 
the condition of the parts in a young Crocodilian embryo, he does 
not point out that Rathke’s statements on the same topic are 
diametrically opposed to his own. The embryo examined by Prof. 
Peters (/. c. p. 595, figs. 1, la) was 70 millimetres, or nearly 3 
inches long. He says that the quadrate bone was ‘“ angelegt,”” but 
contained ‘neither cartilage nor bone ;” so that it is not obvious 
what the histological condition of the part referred to may have 
been. 
But in an embryo of Aligator lucius of less size (2" 2!" long, the 
skull measuring 7!) Rathke (‘Untersuchungen tiber die Entwickelung 
und den Kérperbau der Krokodile,’ 1863, p. 34) found the quadratum 
quite cartilaginous. 
“The quadrate bone resembled in form that of young and adult 
specimens of Alligator luctus, but was narrower and thinner, in 
proportion to its length, in its lower part, which is provided with a 
shallow articular excavation. It consisted of cartilage ensheathed in 
its middle third hy a bone. By its broader and flatter upper half it 
was loosely attached to the outer surface of the cartilaginous auditory 
capsule, in front of and above the fenestra ovalis.... . 
«With the quadiate bones articulated two long and, on the whole, 
slender Meckelian cartilages, which extended to the mandibular 
symphysis. For the greater part of their length they were cylindrical, 
and diminished in diameter very gradually from behind forwards ; 
posteriorly, however, where they were connected with the quadrate 
bones, they were a good deal enlarged. An absolutely and relatively 
short, hook-like prolongation extended beyond the articulation. The 
thinner and longer cylindrical portion of each was loosely invested 
by five very thin, but completely ossified, plates, which enclosed it, as 
in a sheath, though they were separated by larger or smaller intervals. 
At a later period these plates grow and become closely united, thus 
giving rise, as in other Reptiles and in Birds, to the greater part of 
each ramus of the mandible. But of Meckel’s cartilage only the 
enlarged part ossifies, and thus gives rise to the articular piece of 
the lower jaw.” 
How is this discrepancy to be accounted for? Unfortunately I 
have been able to procure no specimen of an embryonic Crocodile 
so small as either of those here described ; but Prof. Peters’s figures 
(Taf. i. figs. 1, la) leave very little doubt on my mind that the 
cartilage which he marks m, and imagines to be his ‘ malleus” 
(the suprastapedial cartilage) is really the quadratum, the articula- 
tion of which with Meckel’s cartilage takes place in the ordinary 
way, and that 7, called the columella (or stapes), is neither more 
nor less than the pterygo-palatine cartilage. The most cursory glance 
