304. COPE. [Vou. IL. 
of the stapes confirm this view, since they are those of land 
salamanders, as distinguished from those of aquatic habitat. 
Second. There are also three types of relation between the 
ceratohyal arch and the skull. In the one there is no connection 
between the two, as in the Pseudophidia. Secondly, the con- 
nection is by ligament. This is seen in Proteida, Trachysto- 
mata, and all Pseudosauria except the Amblystomidz and Pletho- 
dontide. The last two families embrace the third type, in 
which the ceratohyal is articulated by suture with the quadrate. 
This last type is the most specialized, since the larve of those 
families display the connection between the ceratohyal and the 
skull similar to that seen in the types first and second. Thus 
the Salamandridz, which are superior to the Plethodontidze 
in their osseous carpus and tarsus, and opisthoccelous vertebree, 
have the hyoid connected with the skull, as in the larvze of the 
latter. 
Third. Ata stage in the history of the development of the 
Salientia, the relations of the stapes and of the ceratohyal to 
the skull are the same as in a transitional stage of the Urodele 
family of Plethodontidz ; or, taken separately, the relations of 
the stapes are those of Proteida, Trematodera, and larval Pseu- 
dosauria, while the relation of the ceratohyal is as in adult Pletho- 
dontidz and Amblystomide. This is when the interstapedial 
cartilage connects the stapes with the posterior face of the 
quadrate cartilage, and where the ceratohyal articulates with the 
posterior face of the quadrate at its distal part. 
Fourth. It is not probable that the epistapedial forms an 
integral part of a single primitive element, which includes 
the other osstcula auditus, as it originates independently of 
the interstapedial and mesostapedial. 
Fifth. The interstapedial and mesostapedial do not, at any 
time in the history of the development of the genus Rana, form 
any part of the ceratohyal or meckelian ventral arches. As the 
incus and malleus of the Mammalian ossicula auditus are seg- 
mented from the proximal parts of these arches, embryology 
indicates that they are not homologous with the ossicula of the 
Salientia. From this point of view, the latter form a special 
line of development, distinct from that displayed by the Mam- 
malia, unless the developmental record has been greatly falsi- 
fied by caznogeny. From the embryological standpoint, it 
