DEVELOPMENT OF THE SKULL IN THE LACERTILIA. 
613 
developed to the highest pitch; it is suppressed in the Chamseleon, and small in the 
“ Chelonia.” 
For many years I have been familiar with this bone so far as it is seen in Reptiles, 
but its genesis was hidden from me; by naming it simply from its position , I named it 
truly. Cuvier named it from its form , and the same name, also, was given to the 
auditory stapedial stem, namely, “ columella ”—a name which can only be retained for 
the last ossicle. 
But in working out the skull of the Axolotl, and tracing it into that of the 
Amblystoma (“Skull of Urodeles,” Plate 27, fig. 7, e.pg., p. 566), and also in working- 
out the Menopome, the Newt, and other kinds of tailed Amphibia, I came upon its 
true (very simple) morphological meaning. 
In those forms, which in their larval state are but a step beyond the “Dipnoi,” we 
can find the correlation of the outer and inner skeletal elements, as they are becoming 
attracted to each other, by what may be called organic affinity. 
The large symplectic process of the mandibular suspensorium, the pterygoid cartilage, 
has no development in the lowest forms of “ Urodeles,” namely, in Proteus and 
Menobranclius, and it appears rather late in the larvae of the higher (metamorphic) kinds. 
The bony (pterygoid) plate in these low forms and in the young larvae of the higher 
kinds, is not distinct from, and grows as a process of, the dentigerous “ palatine,” close 
to the corresponding dentigerous vomer—two patches of teeth, bound together by 
spreading bone, and entirely independent, at first, of the chondrocranium. 
The process from the bony palatine which grows backwards to meet the pterygoid 
cartilage as it grows forwards, is then fretted off from its bony root, soon applies itself 
to the cartilage, metamorphoses much of it into bone, but carefully, in most cases, 
leaves a small, obliquely-placed rod, unossified; this tract was once a separate post¬ 
palatine. 
This rod, lying in a groove of bone, becomes an ennucleated rudimentary “ epi¬ 
pterygoid,'’ and the gentlest metamorphic touch, sheathing it with an independent film 
of bone, would give us the exact counterpart of the Chelonian “ epipterygoid.” 
In the Lizard, as we shall see in the 6th or penultimate stage, this part, and the 
two plates of cartilage on the pterygoid (a membrane bone), are all the cartilage we 
find in the symplectic region of the Lizards’ mandibular suspensorium ; the foot-shaped 
antorbital cartilage belongs to the next, or palatine arch. 
Note also, that here, where the symplectic or pterygoidean parts are so largely 
developed, we have, as a correlate, the suppression of the “ orbital process ” or 
“pedicle” of the mandibular pier, only the “otic process” appears, on the quadrate 
(Plate 42, fig. 3, q.). 
In the Chelonia, where the epipterygoid is small, the “ pedicle ” is small, but distinct; 
in Birds, where the epipterygoid is never more than an ascending process or hook 
(“hamular process”), there the pedicle or orbital process of the quadrate is very large, 
nearly as large as the otic process. 
