No. 2.] HYOIDS AND OTICS OF BATRACHIA. 301 
Amphiumoidea. The extremity is connected with the quadrate 
bone by a hyosuspensorial ligament. In Salamandra the cera- 
tohyal and the ligament are of moderate length. 
In the Pleurodelidz the arrangement is as in the Salamandri- 
dz. In some of the species the ceratohyal is greatly elongate. In 
the Diemyctylus torosus the free extremity of the ceratohyal ex- 
tends to the inferior line of the occipital condyle, carrying with 
it the hyosuspensorial ligament. This ligament is elongate, and 
arises from the proximal part of the posterior border of the quad- 
rate cartilage (PI. II., Fig. 3). Inthe D. virtdescens this pecu- 
liarity is carried still further. The ceratohyal extends to the 
lateral crest of the exoccipital, and is received into a fossa of its 
inferior surface, as has been pointed out to me by my friend Dr. 
E. E. Galt. The hyosuspensorial ligament extends from the 
proximal part of the quadrate cartilage beneath the ridge men- 
tioned to the apex of the ceratohyal (Plate II., Fig. 4). 
TRACHYSTOMATA. 
In Siren the stapes is osseous. Its columella is replaced by 
the stapedius muscle, which extends posteriorly. It has no 
connection with the suspensorium. The quadrate is cartilagi- 
nous. The ceratohyal is large and is much produced distally. 
It is connected with the posterior part of the quadrate, the ex- 
occipital, and the stapes by a wide hyosuspensorial ligament. 
It is inserted on the anterior side of the ceratohyal oppo- 
site the quadrate, and is interrupted by a hyosuspensorial 
cartilage, as in Cryptobranchus. 
SALIENTIA. 
Laurenti. Axura Dumeril. 
The stapes in this order resembles that of the Urodela. It is 
an oval disc without distinct process, and gives insertion to a 
stapedius muscle near its centre. But this order differs totally 
from the other existing orders, in the presence of a chain of 
ossicula auditus, which extends from the border of the stapes to 
the dermal membranum tympani. There are three of these, 
which have been named the interstapedial, the mesostapedial, 
and the epistapedial. The interstapedial is a bony style with a 
cartilaginous basis which originates alongside of the anterior 
