638 The American NatJiralist. [July, 
which it articulates with the short basal stem of a trifid extra columel- 
lar cartilage or malleus. The lower process of this trifid malleus is 
connected with the mandible by a cartilaginous or partly ligamentous 
string, for the reception of which the quadrate forms a bony canal. 
The whole string is originally cartilaginous. The hyoid arch has 
entirely disappeared as far as ceratohyal and stylohyal pieces are con- 
In Sphenodonia the top end of the hyoid is fused with the extracolu- 
mella. In Gecko it is attached to the cranium, as in the Mammalia, 
but in most lizards the proximal portion of the hyoid is removed from 
the skull, and remains otherwise well developed. In the Ophidia and 
in birds, as in Crocodilia and Chelonia, the proximal part of the hy- 
oid becomes reduced and lost. In Ophidia and in Chamaeleo the 
extracolumella gains an attachment to the quadrate, squamosal or 
pterygoid, while its connection with the mandible and the tympanum 
is lost. The chamaeleon has no tympanum, and those parts of the 
extracolumella which in other types would be attached to the tym- 
panum, are here attached to and fused with the quadrate. In birds 
the arrangement of the auditory ossicular apparatus is very similar to 
that of the monitors. In the adult the whole hyoid bar is absent, with 
the exception of a small cartilage. 
In mammals, as is well-known, the ossicles of the ear are usually 
four, although the small lenticular element which lies between stapes 
and incus frequently remains cartilaginous, and is occasionally ab- 
sent. The hyoid has no connection with either mandible, palate, 
quadrate, or with the ossicular chain, but its upper end is fused 
with the cranium behind the tympanic ring. Many various 
views have been held respecting the origin, of the auditory ossicles. 
Tindemann (1810) held that the entire ossicular chain of mammalia 
was equivalent to the columella of birds and reptiles, and that the 
quadrate equals the zygomatic process of the squamosal. Reichert 
(1837) derived the malleus from the articular element of the mandible, 
the incus from the quadrate, and the stapes from the end of the hyoid. 
Gegebaur agreed with Reichert as regards the malleus and incus, but de- 
rived the lenticulars and the stapes respectively from the symplectic and 
the hyomandibula. Peters (1867) held that all the ossicles were devel- 
oped from Meckel's cartilage, and that the quadrate had become the tym- 
panic bone. Huxley (1867) and Parker both held that the quadrate 
of birds and rept^ps became the malleus of mammals, and that the 
incus and lenticular were derived from the hyomandibula. Huxley also 
held that the stapes is of hyomandibular origin, but Parker was inclined 
