Discription of a Saurian foiir,d in Kansas — Cragin. 405 
Trinacromerum as the generic and hentonianwn as the specific 
name, and which may be characterized as follows: 
Generic Character's. — Muzzle long and narrow, with a median 
carina above and below. Teeth conical, curved, with plicate 
enamel, those of either jaw forming with the corresponding of 
the other a regularly spaced series of shearing pairs. Neck 
short. Vertebrae amphicoelous, with shallow articular concavi- 
ties; the neural arches anchylosed with the centra without 
trace of suture; neural canal spacious; centra of the cervical 
vertebrae quadrate, transverse, and depressed; those of the dorsal 
vertebras subcircular, cylinders generated by a line that presents 
a slight convexity toward the axis, the cylinders broader than 
long. Sacrum composed of two cylindrical vertebrae with mas- 
sive diapophyses whose stout short ribs meet distally for the 
support of the ileum. Swimming paddles long and narrow, 
those of the anterior and posterior pairs not very unequal in 
size, the supposed posterior being slightly the larger; both fur- 
nished with numerous phalanges (many more than in plesio- 
sauroid* generally); humerus and femur stout, proximally 
expanded into a subspherical and obliquely directed head with 
pitted surface for the articular cartilage; greater tuberosities 
and trochanters prominent, separated from the head by a con- 
striction which, passing round the bone a little below the artic- 
ular surface, forms a short but distinct neck; a large deltoid 
ridge and impression; proximal portion of the shaft of both 
humerus and femur subcylindrical, showing, as do the head and 
neck of the same, a slight compression in a plane that makes a 
large angle with that of the middle and distal portions which 
become rapidly compressed to the flat and very broad distal 
extremity; this extremity presenting three iiiterangulated con- 
cave facets, with the anterior two of which articulate the radius 
and ulna (or tibia and fibula) and with the third and posterior 
of which articulates a pentagonal carpal-like bone, followed by 
a second which is smaller and tetragonal. Radius, ulna, tibia, 
and fibula transverse and subquadrilateral. Tarsals and carpals 
six, polygonal, arranged in two transverse rows; intermedium 
hexagonal, transverse, related to the paddle as in Flesiosaurus. 
Specific Characters. — Premaxillary portion of the muzzle 
considerably higher than the mandibulary, both portions boat- 
shaped, median keel of either narrow but pronounced, that of 
