ON SOME NEW AND LITTLE KNOWN CEEODONTS. 
181 
tl•ans^erse processes are long, but not very broad; they are curved sharply forward and 
terminate in a point ; the spines are of moderate height, but have great antero-poste- 
rior extent and incline strongly forward, that of the last vertebra is nearly vertical. 
HycBaodon shows in a very marked degree the creodont peculiarity of the lumbar 
zygapophyses ; the prezygapophyses are exceedingly concave and curve far over; into 
these the convex, nearly cylindrical postzygapophyses, fit. The metapophyses are 
small and in the last three vertebrae rudimentary ; small anapophyses are present. 
The sacrum consists of three vertebrae ; the first has a broad and depressed cen- 
trum, with very large pleurapophyses and long oblique transverse processes ; the pre- 
zygapophyses are shaped as in the lumbar region, but are much lower ; the spine is 
low and not ankylosed with that of the succeeding vertebra. The second sacral is of 
about the same length as the first, but much narrower ; only the anterior comer of the 
pleurapophysis is in contact with the ilium which is carried almost entirely by the 
first vertebra ; the spine is low. The third sacral is the smallest of all. No caudal 
vertebrae are preserved, but Hycenodon probably possessed a long tail. 
Ribs . — The anterior ribs are very broad and flat; this flattening is marked as far 
as the sixth; behind that the ribs become more rounded. The first rib is especially 
broad and has an exceedingly large and convex tubercle ; the second is similar but 
has a smaller tubercle ; in the others the tubercle is less conspicuous and somewhat 
saddle-shaped. 
Tlie fore-limb is proportionally longer and heavier than in Mesonyx, but strik- 
ingly weak when compared with the modern Carnivora. The humerus (which is 
somewhat crushed and has lost its proximal end) has a long and rather slender shaft, 
with a prominent deltoid ridge; the supinator ridge is low; an epicondylar foramen is 
present, as is also the supratrochlear; the anconeal fossa is broad and very deep; the 
trochlea has a prominent ridge and the internal edge is prolonged downwards ; the 
condyles are not very prominent. This humerus agrees quite well with that of II. 
( Taxotherium) parisiensis, as figured by De Blainville (Subursus, pi. xii), but differs 
in the presence of the supratrochlear foramen and the greater prominence of the 
intertrochlear ridge. 
The xdna is rather short and stout ; the shaft, though flattened, is heavy, and is 
convex on the inner, deeply channelled on the outer side ; the olecranon, as in the 
creodonts generally, is very prominent; the sigmoid notch is deep and the radial 
facets occupy nearly the entire anterior face of the lower end, only a small portion of 
this face is in contact with the humerus. De Blainville’s figure differs from this 
specimen only in the somewhat reduced radial surface. The distal end is much com- 
pressed and ends in a rounded-convex facet for the cuneiform. 
The radius has a broad proximal end, Avhich occupies nearly the whole breadth 
of the humeral trochlea; the upper part of the shaft is broad and flattened; below it 
becomes rounder and much stouter ; the distal end is expanded and thickened, espc- 
