65] THE NASAL ORGAN IN AMPHIBIA—HIGGINS 65 
Cope (1889) misled by a supposed ethmoid bone in Amphiuma placed 
the Caecilians with the Urodeles, in which view he was later supported by 
the Sarasins (1890). Kingsley (1902) definitely determined the position 
of the Caecilians and maintained Huxley’s conclusion that the Gymno- 
phiona have probably separated from the ancestral Amphibia back in the 
early Carboniferous period. The nasal capsule of Epicrium is further 
evidence of the wide divergence of this group from all other Amphibia. 
The Anura are readily separated into two groups, on the basis of the 
nasal skeletons, and these agree with the extablished classification into the 
Aglossa and the Phaneroglossa. Cope’s subdivision of the latter into 
Arcifera and Firmisternia is not so readily recognized in the nasal capsules 
of my material, although there are more resemblances between the cap- 
sules of Bufo and Hyla, than of either with that of Rana. 
AMPHIBIAN ANCESTRY 
The Amphibians appear, as Stegocephals, in the Carboniferous period, 
and although from the first they are considerably diversified, there is not 
known a single trace of any tetrapodous vertebrate in the Devonian with 
the sole exception of a single footprint from the Pennsylvanian. In the 
Devonian and somewhat earlier, fishes belonging both to the Dipnoi and to 
the Crossopterygian ganoids occur, and both of these piscine groups have 
been invoked by various zoologists as the ancestors of the Amphibia, 
possibly the tendency of the evidence at present favoring the Crossoptery- 
gians. 
All of the amphibians of the Carboniferous, with the possible exception 
of Pelion, were caudate. Moodie (1916), the latest to study these ancient 
forms, is inclined to regard Micrerpeton, a small Salamandra-like form, as 
representing the ancestors of the modern groups, with Necturus as an 
annectant genus. He bases this conclusion upon the resemblances of the 
skull, the form of vertebrae and ribs, the peculiarities of the lateral line 
system, and the presence in both of ‘ventral scutellations,’ a view which 
closely resembles the earlier ideas of Cope. 
But it would seem as if Moodie was leaning upon a weak reed in invok- 
- ing ventral scutellations as an argument, no matter what view one may 
take with regard to the other points of resemblance. It is well known 
that many of the Stegocephals had ventral scutes, plates or bars upon the 
ventral surface of the body, but the universal view is, that these structures 
were purely dermal, belonging like scales of fishes to the skin. Moodie 
cites Wilder as stating that Necturus had small cartilages in the ventral 
region, and apparently he regards these as the homologue of the ventral 
armor of Stegocephals. But there are very important differences between 
the two. 
