EXTINCT AMPHIBIA OF NORTH AMERICA 55 
from the Coal-measures of England. The cross-commissure is con- 
tained within the epiotics. The jugal and the temporal canals form 
a complete ring much as the same canals do in Tvematosaurus. The 
squamosal in 7. ¢abulaius is excluded from the parietal by the exten- 
sion of the epiotic and the postorbital and it is to be noticed that the 
temporal canal has a changed position to correspond with the changed 
condition of the squamosal. ‘This is of considerable interest in con- 
nection with the correlation of the squamosal in fishes and amphi- 
necessary here to state that 
on the basis of the lateral 
fishes has been made. ‘This 
contradicts the results ob- 
tained by Thyng’ from Fic. 9.—The outline of the cranial elements 
embr yo lo g] cal studies, andthe lateral line canals in Tuditanus tabulatus 
bians. This subject has 
aS 
line canals and their arrange- eS A 
Cope. One and one-half times natural size. 
been fully treated in another 
ment in the fishes and the an 
Amphibia the true correla- _, aN 
tion of the squamosal ele- : 
place, and it will only be 
ment in amphibians and ( 
a 
Thyng’s results are noticed 
more fully in the paper 
above cited. The temporal canal has apparently an indication 
of a connection with the supraorbital canal but of this I am not 
sure. The jugal canal occurs on the supratemporal, quadratojugal, 
and it joins the infraorbital on the jugal. The infraorbital is indicated 
by a short portion some few millimeters long under the orbit and the 
rest, i.e., its connection with the jugal canal, is restored. There is 
nothing unusual to be observed in that portion of the infraorbital 
canal which is preserved. The supraorbital canal is indicated by a 
curved, broad, shallow groove on the inner side of each orbit. As 
above stated there seems to be a connection between this canal and 
the temporal but I am not sure. The primitive conditions shown 
in the lateral line canals in 7. tabulatus are the presence of the occi- 
t “Tufts College Studies,” 1906, Vol. II, No. 2. 
