Yoh. 6, 1920 PALAEONTOLOGY: OSBORN AND MOOK 
15 
RECONSTRUCTION OF THE SKELETON OF THE SAUROPOD 
DINOSAUR CAMARASAURUS COPE {MOROSAURUS 
MARSH) 
By Henry FairfieIvD Osborn and CharIvKS Craig Mook 
American Museum oe Naturai^ History, New York City 
Read before the Academy, November 11, 1919 
The principles of modern research in vertebrate palaeontology are 
illustrated in the fifteen years' work resulting in the restoration of the 
massive sauropod dinosaur known as Camarasaurus, the ''chambered 
saurian." 
The animal was found near Canyon City, Colorado, in March, 1877. 
The first bones were described by Cope, August 23, 1877. The first at- 
tempted restoration was by Ryder, December 21, 1877. The bones 
analyzed by this research were found probably to belong to six individuals 
of Camarasaurus mingled with the remains of some carnivorous dinosaurs, 
all from the summit of the Morrison formation, now regarded as of Jurassic- 
Cretaceous age. In these two quarries Cope named nine new genera 
and fourteen new species of dinosaurs, none of which have found their way 
into palseontologic literature, excepting Camarasaurus. Out of these 
twenty-three names we unravel three genera, namely : 
One species of Camarasaurus, identical with Morosaurus Marsh. 
One species of Amphicoelias, close to Diplodocus Marsh. 
One species of Epanterias, close to Allosaurus Marsh. 
The working out of the Camarasaurus skeleton results in both the artic- 
ulated restoration and the restoration of the musculature. The 
following are the principal characters : The neck is very flexible ; anterior 
vertebrae of the back also freely movable ; the division between the latter 
and the relatively rigid posterior dorsals is sharp. Double spines of the 
cervicals and flexible anterior dorsals show through the skin of the restora- 
tion. Spines of the relatively inflexible dorsals, sacrals and caudals 
are comparatively low and broad. The breadth of neck, thorax, and pelvis, 
as shown by the bones, is relatively greater than in other sauropodous 
dinosaurs. The tail had no terminal whip -lash. The scapula is very 
massive and expanded at the summit. The cross-section of the thorax 
is relatively much broader than in other Sauropoda. The general conclu- 
sion is that Camarasaurus was a very broad and massive, slow-moving 
sauropod, in fact, the most massive reptile in proportions that has ever 
been found. 
This study is part of the senior author's research for the Monograph on 
the Sauropoda in preparation for the U. S. Geological Survey. 
