228 REPORT OF NATIONAL MUSEUM, 1901. 



berand its transition from the dorsal to the ventral side; also the transition from 

 the monochoanitic (having only a funnel) to the later doiockoanitic (funnels lost, 

 collars alone remaining) c lition. Enlarged 60 diameters. 



B. Section of Vertebrate Fossils. 



The exhibit of the section of vertebrate fossils comprised a series 

 of specimens representing the Mastodon, Mammoth, andTitanotherium, 

 reproductions of the skeletons of Zeuglodon and Triceratops, and a 

 very complete mounted skeleton of the Cretaceous diving bird Hes- 

 perornis regalis. This last is of special importance, not only as being 

 the first skeleton of this representative of the toothed birds to be 

 mounted and exhibited, but because it threw new light on the struc- 

 ture and attitude of the bird. In ordinary swimming birds the legs 

 are directed downward, beneath the body, but the character of the 

 articulations show that in Hesperornis the tarsi were directed out- 

 ward at right angles to the body. A photograph of the skeleton as 

 exhibited is shown in Plate 7<>. 



The skeleton of Zeuglodon was modeled from material obtained by 

 Mr. Charles Schuchert in Alabama. It comprised practically a com- 

 plete vertebral column, many of the ribs, a good skull containing the 

 complete dentition, and the major portions of the fore and hind limbs. 

 This is a greater amount of material than is present in any other 

 museum, and made it possible for the first time to obtain an accurate 

 idea of the skeleton of this animal. It is shown suspended from the 

 ceiling in the background of Plate 59. 



The skeleton of Triceratops was a full-sized reproduction based on 

 the material in the United States National Museum, which contains 

 portions of fifteen specimens. These include the skull, limbs, lacking 

 phalanges, pelvis, nearly complete vertebral column in advance of the 

 sacrum, and several ribs. The greater part of the skeleton was thus 

 present and restoration was limited to some of the ribs and the greater 

 portion of the caudal vertebras. The reproduction of the skeleton 

 provided the first accurate representation of one of these huge dino- 

 saurs ever placed on exhibition. It is regretted that no more satisfac- 

 tory view of this interesting restoration could have been obtained 

 than that furnished in Plates 58 and 59. This exhibit was accompanied 

 by a small model, some 18 inches in length, and a painting by Mr. 

 Charles Knight, showing the animal as it was supposed to appear in 

 life. See Plates 71 and 72. 



The exhibit for the Division of Geology, it should be stated, was 

 prepared under the direct supervision of the head curator; that of the 

 Di\ ision of Mineralogy by Mr. Wirt Tassin, assistant curator; that of 

 the Section of Invertebrate Fossils by Mr. Charles Schuchert, assistant 

 curator, and that of the Section of Vertebrate Paleontology by Mr. 

 F. A. Lucas, curator of comparative anatomy in charge collection of 

 vertebrate fossils. 



