WILLISTON: .BRACHYSAURUS, A NEW GENUS OF MOSASAURS. 97 
Chidastes. The maxilla are likewise stout, and have twelve teeth 
implanted in each.’ The teeth are remarkably stout, much more 
so than in the other genera, save, perhaps, Zylosaurus. They are 
moderately recurved and are smooth throughout, with a weak 
carina fore and-aft. From the shape of the maxillew, the length of 
the lower jaws, and the breadth of the frontal bone, it is quite 
evident that the rostrum was not much prolonged in front of the 
teeth. 
The frontal bone is remarkably broad and heavy; the orbital 
borders are convex and apparently free, the prefrontal not being 
prolonged back to the postfrontal.. The strong median projection 
behind is very different from the usual shape of this part. The 
borders of the bone are stout and thick. 
The cervical and thoracic vertebre have the centra cordate in 
outline at the convex end, and are relatively small for so large and 
broad ahead. The cervical hypopophyses are free,* but the pro- 
cess for their attachment is not smaller than usual. The pygial 
and caudal vertebrae have their outline subtriangular, much as in 
Tylosaurus. The chevrons, in the caudal vertebre preserved, are 
firmly co-ossified with the centra. 
The coracoid is of the usual shape, and has a deep emargination. 
Perhaps the most peculiar of any of the elements preserved, 
aside from the quadrate, is the humerus. Its proximal end is much 
thickened, strongly convex from side to side, with a projecting 
angle at one side of the middle. The deltoid ridge is narrow and 
proportionally small. There is no radial process, as in Mosasaurus 
and Cidastes, but there is a stout ulnar process, with a large round 
surface, projecting nearly upwards. The free radial border is re- 
markably short, that of the ulnar side much longer and curving 
obliquely forward to the ulnar tuberosity. 
A single paddle bone (fig. 7) is of such peculiar shape that I can 
not place it. 
Altogether, the animal possessed a remarkably stout and broad 
head, with stout jaws and teeth, and evidently short, broad and 
stout paddles, and short body. 
Measurements: 
QuadHAte! Ota Hlen ets a tenr iy ani k Sch airy ml kites gue mo O stunts 
PEVOTUAL DOLE Gees Gite ie enor viatas wamnnlvegiNtys ais Museu unm iche Uae) 
Mandible, length from artic tt ution, toextremiuty .. i... 650 
ia length: of dental senesiy voi aCe eke 
i MHC UA OD POSWa ASU T COGN Mrika cleanin sta it OG) 
*The co-ossification of the cervical hypopophyses is of minor value. A specimen of 
Clidastes tortor Cope in the museum has them firmly united throughout. 
