520 MOODIE. [Vor. XIX. 
ably gave rise. The other groups of extinct Amphibia are, 
of course, out of the question so far as being ancestral to the 
modern Amphibia is concerned. The Aistopoda, when we 
first know them, are highly specialized, snake-like Amphibia 
and could not have given rise to animals with legs since it 
is well-known that they are descended from forms with well- 
developed limbs as is evidenced by the vestigial pectoral gir- 
dle in Ptyonius. The Temnospondylia and Stereospondylia, 
which are closely related, were also highly specialized along 
their own line, and like the Pterodactyles went out of exist- 
ence completely and, so far as we know, left no descendants. 
There is certainly nothing in the structure of the Branchio- 
sauria to prevent their being ancestral forms to the modern 
Amphibia. There is much in favor of it. The idea is not a 
new one but has been suggested by Baur and others. We have 
here, however, for the first time, something definite on which 
to base our conclusions.” This matter is discussed more fully 
elsewhere. The cranium of the Branchiosauria, like the 
modern Amphibia, is never grooved by the lateral line canals, 
but the system was undoubtedly present on the skull in the 
skin, much as it is in the modern forms. 
In the Microsauria, although there are numerous forms 
known, there have been but few observations made on the 
lateral line system. There are evidences of the canals on a 
skull and mandibles of Diplocaulus, Andrews (15) has 
observed rows of pits on the skull of Ceraterpeton galvani 
Huxley from the Carboniferous rocks of Staffordshire, Eng- 
land, and the writer has recently detected them on an excel- 
lent skull of Tuditanus tabulatus Cope from the Linton, Ohio, 
beds and traces of the supraorbital canal have been observed 
on the skull of Stegops divaricata Cope from the same local- 
ity. 
In the Ceraterpeton specimen (Fig. 7) there are evidences 
of the lateral lines on the posterior and upper portions of the 
skull only. They consist in the occipital cross-commissure, 
the temporal canal and a portion of the supraorbital canal. 
