Z MEMOIRS OF THE CARNEGIE MUSEUM 



the subsequent exhumation of the remains, especially to such part of this work as 

 has been accomplished by nature, there has resulted in the first instance, as a rule, 

 only a partial preservation of each skeleton, and in the second, frequently the com- 

 plete or partial destruction of such parts of the skeleton as were preserved in the 

 first instance. It seldom happens that in two fossil skeletons, or even skulls, no 

 matter how perfect they may appear, there will not be exhibited in one characters 

 wanting in the other, due either to age, sex, or differing degrees of preservation. 



Of the many exasperating disappointments just referred to, that mentioned by 

 Professor Osborn in the second paragraph of his introduction to the description of 

 a skeleton of Diplodocus, published as Part V., Vol. I. of the Memoirs of the 

 American Museum of Natural History, may be cited as a common example. He 

 says, in speaking of the discovery of the specimen, ''At one time strong hopes were 

 aroused that the entire animal would be found together. The long tail stretched 

 off parallel with the cliff, interrupted only by a small gulley which had cut through 

 a small section of the caudal s. In front of the sacrum the dorsals stretched forward 

 in a promising way, but the centra were wanting, and finally nothing but the neural 

 arches remained." Strikingly similar disappointments have attended the discovery 

 and unearthing of at least a half dozen other skeletons of Diplodocus. Happily, 

 however, in the preserved and recovered remains of these various skeletons different 

 parts of the frame are represented ; so that by combining all, we are enabled to 

 study the restored skeleton almost in its entirety, though still incomplete, in at least 

 one important character, to Avit, the fore feet. 



The difiiculties arising from the fragmentary nature of which most remains of 

 vertebrate fossils consist when found imbedded in the rocks, are greatly increased in 

 the Dinosauria by the enormous size attained by the individual animals in many 

 genera. These difficulties are especially applicable to Diplodocus and the allied 

 genera constituting the Sauropoda, which include the remains of the largest land 

 animals known to science. These animals frequently attain to a length of over 

 sixty feet, and there is evidence that representatives of some of the larger genera 

 fell but little, if any, short of one hundred feet in length. Every student of the 

 modern Cetacea is well aware of the great difficulty encountered in undertaking a 

 compi-ehensive study of the osteology of that order of mammals, due chiefly to the 

 trouble and expense incurred, on account of their size, in bringing together, prepar- 

 ing and caring for, sufficientl}'^ complete osteological collections. In the Dinosauria 

 these difficulties are rendered infinitely greater, so that the task of bringing together 

 an even fairly representative collection in any one institution, even though its re- 

 sources may be considerable, is rendered exceedingly difficult, if not quite hopeless. 



