8 THE ROYAL SOCIETY OF CANADA 
by teeth. The remaining forms belong to the genera Acipenser, Lepi- 
dosteus and Rhineastes of different suborders of the Actinopterygii. 
Scapherpeton tectum, of uncertain position among the tailed batra- 
chians is the sole representative of its class at this horizon. 
The Reptilia claim our attention next. Most of the principal sub- 
divisions are represented, and the many genera and species shew a 
tendency toward rapid development and specialization. Sauroptery- 
gians of the Plesiosaurian type were present but their remains are rare; 
turtles and dinosaurs were especially numerous. The Rhynchocephalian 
genus Champsosaurus is represented by vertebrae, and dubious Lacer- 
tilian remains occur in the form of teeth. A single Crocodilian genus is 
also found to add to the interest of this important and varied fauna, 
The turtles are of the superfamilies Amphichelydia, Cryptodira and 
Trionychoidea, and in themselves form an important series of fossil 
species; they may be noticed in order as follows :— 
Amphichelydia represented by Baënidæ of the genera Boremys, 
Baëna and Neurankylus. This family dates from Jurassic times and 
has handed down a number of primitive characters to its later members. 
Boremys is especially interesting in having, as archaic features, well- 
developed supramarginal scutes and a preneural bone in the carapace, 
and mesoplastra meeting in the median line in the plastron. Neuranky- 
lus may be mentioned as having the unusual number of nine costals in 
the type. The Baënidæ and the nearly related Pleurosternide were 
adapted for progression on land and, according to Hay, inhabited lakes 
and rivers and were good swimmers, but had no special modification of the 
limbs for swimming. 
Cryptodiran turtles of the family Dermatemydidæ, and belonging 
to the genera Basilemys, Compsemys and Adocus, of which Basilemys, 
a large swamp turtle, had, in the Judith River species variolosa (Cope), 
a particularly strong and thick shell reaching a length of about thirty 
inches. The Cryptodira are remarkable, as a group, for their wide 
geographical distribution and for their variety of habitat. 
Also a number of Trionychoidea, river- or mud-turtles, specially 
adapted for life in the water, of the families Plastomenide and Triony- 
chide. Of these two families the former is extinct, but the latter is 
represented by many living species, the fresh-water, carnivorous, soft- 
shelled turtles of the present day. 
Altogether nine species of turtles are known from the Judith River 
formation of the west. 
It is to the Dinosaurs of this formation that the greatest interest 
attaches. The discovery of their remains in the ‘ bad lands” of Red 
Deer river brought to light new forms ancestral to those of the Laramie 
Cretaceous of a later date. Also on account of their state of rapid 
