interior structure is cancellous. The chevron bones differ from those of most known Dinosaurs in having the superior articular ends of the rami not united, but separated from each other, as in the Mosasauria with free hæmapophyses.
Some of the dimensions of this skeleton are as follows:
Length of centrum of anterior dorsal vertebra....................................................................................................................................................................................................................................................220·mm
Transverse diameter of anterior face....................................................................................................................................................................................................................................................310·
Amount of convexity....................................................................................................................................................................................................................................................90·
Length of centrum of lumbar vertebra....................................................................................................................................................................................................................................................240·
Transverse diameter of anterior face....................................................................................................................................................................................................................................................410·
Length of median sacral vertebra....................................................................................................................................................................................................................................................250·
Expanse of its transverse processes....................................................................................................................................................................................................................................................760·
Length of centrum of median caudal....................................................................................................................................................................................................................................................190·
Length of posterior caudal....................................................................................................................................................................................................................................................185·
This animal must have been between fifty and sixty feet in length, and more than thirty feet in height when erect.
Another huge Dinosaur, apparently of the same genus, but of smaller size, is represented in the Yale Museum by the more important parts of a skeleton, in remarkable preservation. In this specimen the cervical vertebræ have the walls of the centra very thin. The caudals preserved are elongated and slender, indicating a long tail. The femur is comparatively short, and without a third trochanter. The great trochanter is much lower than the head of the femur, and continuous with it. The metapodial bones indicate a foot of medium length.
The following measurements indicate the size of the reptile:
Length of femur....................................................................................................................................................................................................................................................1050·mm
Transverse diameter of proximal end....................................................................................................................................................................................................................................................340·
Transverse diameter of distal end....................................................................................................................................................................................................................................................290·
Length of posterior caudal vertebra....................................................................................................................................................................................................................................................145·
Vertical diameter of anterior articular face....................................................................................................................................................................................................................................................110·
The known remains of this species are from the same geological horizon as those above described. They indicate an animal at least thirty feet in length.
This genus may be distinguished from any known Dinosaurs by the vertebræ, which are peculiarly modified to ensure lightness. Although apparently not pneumatic, they have the weight of the centra greatly reduced by deep excavations in the sides. Some of them have the centra hour-glass in form,
