58 MEMOIRS OF THE CARNEGIE MUSEUM 



The restoration at once reveals the unusual proportions of Diplodocus. The re- 

 markable long neck and tail contrast strikingly with the short body. The hind limbs 

 are longer than the fore limbs, and this fact, together with the enormous elevation 

 of the spines of the sacrals and posterior dorsals, fixes the sacral region as the highest 

 in the vertebral column, a determination first made by Osborn. The powerful ilia, 

 firmly united to the rigidly coossified sacrals with lofty coalesced spines, together 

 with the other pelvic elements proportionately well developed, at once emphasizes 

 the paramount importance of the pelvic region and fixes it as the center of power 

 and motion. The elevated spines, long chevrons, and broadly expanded and rugose 

 diapophyses of the anterior caudals, indicate for this region a very powerful mus- 

 culature which in life enabled this appendix to serve both as an effective weapon 

 and an important organ of locomotion both for swimming when in water and as a 

 balancing organ when on land, while the modified nature of the chevrons of the 

 mid-caudal region indicate the point of contact of the tail with the earth attending 

 the different positions habitually assumed during the life of the individual. The 

 body proper was abnormally short in comparison with the neck and tail. There 

 were no true lumbars, all the vertebrse of the dorsolumbar region having borne ribs. 

 While the body proper was unusually short, it was deep, as indicated by the ossified 

 ribs of the mid-dorsal region, which have a length of over five feet, while the abso- 

 lute girth of the body was probably much increased by cartilaginous abdominal and 

 sternal ribs, which latter doubtless served to attach the ossified ribs to the sternal 

 elements. Thus, notwithstanding the extremely short nature of the body of Diplo- 

 docus, the capacity of the abdominal and thoracic cavities were rendered adequate 

 by its great depth. Moreover, the actual length of the thoracic cavity is much 

 increased from the scapulas being partially swung from the posterior cervical. 



The fore limbs and feet of DijAodocus, and, indeed, of the Sauropoda generally, 

 are less perfectly known than any of the other portions of the skeleton. In the 

 present restoration they are entirely taken from materials in the collections of the 

 American Museum of Natural History in New York. Concerning the humerus, 

 radius and ulna, there can be no mistake, as these are drawn from photograplis of 

 actual specimens loaned by Professor Osborn for the purpose. Of the arrangement 

 of the elements of the manus there is much less certainty. As yet no manus of 

 Dvplodocus or of the other genera of Sauropoda has been found in position. The 

 lack of a close and exact articulation between the bones in the Sauropoda renders 

 it impossible to place the diflferent elements of the manus, Avhen found separated, 

 in their exact and proper positions with a degree of absolute confidence. Professor 

 Osborn in his study of the limbs of Dinosaurs has considered the fore feet of the 



