388 Miscellaneous. 
slip occurs in the frozen soil of the Siberian coast, which never thaws, 
even during the greatest heat of the summer, to a depth of more than 
2 feet; and in this way, within a period of a century and a half, 
five or six of these curious corpses have come to light from their icy 
graves.—From a Report by Mr. Lumley, H.M. Secretary of Embassy 
and Legation, Russia, 1867. 
+ 
On the wnon of the Tympanic Bone with the Lower Jaw occurring 
in the Marsupials during development, as a fresh proof of the agree- 
ment of this bone with the os quadratum of the other classes of 
Vertebrata. By Professor W. Prrmrs. 
The articulation of the lower jaw in the Mammalia is effected, as 
is well known, by means of a condyle, which fits into an articular 
cavity of the zygomatic process of the temporal bone, either directly 
or by the mediation of an interarticular cartilage, whilst in the 
other classes of Vertebrata the lower jaw is united, by means of an 
articular cavity, with the condyle of a bone which, after Hérissant’s 
example, is usually called the os guadratwm. 
This bone is either articulated to the cranium (Birds, Lizards, 
Snakes), or united to it by suture (Crocodiles, Tortoises, Batrachia).. 
In the former case it may assist in the formation of the tympanic 
cavity and in the attachment of the tympanic membrane; in the. 
second it always does so. This bone may be united to various parts 
of the temporal bone, and to the pterygoid, sphenoid, and occipital 
bones. Of all these unions, that with the temporal bone, and, 
indeed, with its squamous portion, is alone constant, whilst all the 
others may be wanting. 
The question, with what part of the mammalian skull the qua- 
drate bone is homologous, has given rise to many disputes, and has 
been answered in various ways :— 
1. Hérissant regarded the ascending ramus of the lower jaw § as 
the part corresponding to it. 
2. Tiedemann, Platner, and apparently Kostlin regard the qua- 
drate bone as a part separated from the squamous (and petrous) por- 
tion of the temporal. 
3. Geoffroy St.-Hilaire regarded the os tympanicum with the pro- 
cessus styloideus as representing it. 
4. Oken, Cuvier, Blainville, Spix, Meckel, Carus, R. Wagner, 
Hallmann, Stannius, Owen, and others interpret it as the os aie 
anicum. 
5. Reichert, O. Schmidt, and Huxley declare that, as Carus had 
previously supposed, the incus or the middle ossicle of the ear in the 
Mammalia is the quadrate bone of the other Vertebrata. 
I had hitherto adhered to the opinion that the os tympanicum of 
the Mammalia was homologous with the os quadratwm of the other 
Vertebrata, as also used originally to be indicated by J. Miiller, in 
his lectures, whilst subsequently he used the expression ‘ quadrate 
bone.” To me the proof of this interpretation lay in the similar 
position of the bone in its relations to the tympanic cavity and 
membrane, and in the union of the bone with the sphenoid occurring 
~ 
