Reviews—Dr. van Hoepen—Stegocephalia, Senekal. 88 
his heels”. Does the public realize that in Californian, unlike 
Scottish, universities earthquakes are more usual than undergraduate 
Claes.) 2 
One does not look to a book of this kind for original observations 
or ideas, and it is in fact difficult for a reviewer whose knowledge is 
less exhaustive than that of Professor Gregory to decide when an 
opinion is taken from elsewhere, or when it has just left the writer’s 
fertile brain. The comparison of the Old Red Sandstone to the 
shingle rivers of New Zealand (p. 204); the solution of the difficulty 
in correlating American, British, and Scandinavian glaciations by 
a bold denial of any synchronism at all (p. 281); the ‘‘ explanation 
of the simultaneous extinction of many different kinds of animals” 
as due to-a reduction in their rate of breeding ‘‘ by slight changes in 
climate and food-supply that occurred at periods of great geographic 
change’’ (p. 293): to select these ideas as novelties may be only to 
expose one’s lack of learning. Fortunately the knowledge of every 
man, even in his own science, is always less than his ignorance; so 
that the most learned geologist may well profit by a reading of this 
popular summary. 
II.—SrreocepHaria or Sunexat, O.F.S. By Dr. E. C. N. van 
Horpen, M.I. 
HE material described in this paper is of very great importance, 
because it represents the only satisfactorily preserved large 
rachitomous Stegocephalian of Upper Permian age yet found. Dr. van 
Hoepen’s excellent description is unfortunately marred by his unsatis- 
‘factory illustrations. These are rather poor half-tone blocks of 
photographs and, as always, fail to show the really interesting 
structural details. Uyriodon senekalensis, as the form is called, is 
a large animal of a flattened body form, with short and rather feeble 
“limbs. The skull is only partially preserved, the important occipital 
region being largely missing. The exoccipital and basi-occipital appear 
to be extremely similar to those of Hryops, but it seems to the 
reviewer that the bone described as the basisphenoid is really only 
the posterior end of the parasphenoid, from which it is said to be 
indistinguishable. In Hryops the basisphenoid is a very spongy bone, 
whose lower and lateral surfaces are completely sheathed by the 
parasphenoid, which even forms a large part of the basipterygoid 
processes, the cores of which are, however, formed by the cartilage bone. 
In a Triassic type near Capztosarus, and apparently in that animal 
itself, the basisphenoid is only represented by a small very spongy 
ossification round the sella turcica, and the pterygoids unite by suture 
with the edge of the flat expansion of the back of the parasphenoid. 
Judging from the description and figure, Myriodon in this region is 
an exact intermediate between the Lower Permian Hryops and the 
Triassic forms. 
The description of the lower jaw corresponds with that which the 
reviewer arrived at when, through the kindness of Dr. v. Hoepen, he 
had an opportunity of examining it. At that time, before the real 
structure of the Stegocephalian mandible, as described by Professor 
