532 MOODIE. ion, Xaaeee 
accompanying cut is a copy. The skull of Mastodonsaurus 
differs greatly from the other skulls described in the large 
size and posterior position of the orbits. This has had an 
effect on the arrangement of the lateral line canals. The 
temporal canal is deflected strongly downwards and its union 
with the infraobital takes place to the side of the eye. The 
jugal canal according to Fraas’s figure does not touch the 
supratemporal. In fact the canal is not represented in its 
most posterior portion. It may have had the course indi- 
cated in Fig. 16. The supraorbital is weakly connected with 
the jugal and with the temporal canal. It has the usual course 
forward and ends near the nares. The only character of 
interest in connection with the infraorbital canal is the dis- 
tinct bend near the anterior termination as though it were a 
remnant of the former connection between the infra- and 
supraorbital canals through the intervention of the antorbital 
commissure. It is to be noticed that the temporal barely 
cuts the outer edge of the squamosal. 
The skull of Trematosaurus brauni Burmeister (16) has 
already been figured and described in this connection by Baur 
and Miall, although the figures given by both of these authors 
are inaccurate im detail when compared with the original 
drawing of von Meyer. Fritsch in his translation of the re- 
port published by Miall also copies his figure and thus con- 
tinues the inaccuracies. There is nothing unusual in the 
Trematosaurus (Fig. 17) except the strong development of 
canals. The occipital cross-commissure is well developed and 
is contained within the borders of the epiotics. The temporal 
has no connection with the supraorbital and the antorbital 
commissure is well developed. There is no anterior com- 
missure. It is to be noticed that the squamosal element is 
clearly cut by the temporal canal which ends at the ear slit. 
It was stated above that there was rarely any evidence of 
an occipital cross-commissure in the Stereospondylia but 
Trematosaurus seems to be an exception to this rule. There 
may be others. 
The skull of Anthracosaurus from the Carboniferous of 
