62 EEPOKT OF NATIONAL MUSEUM, 1912. 



The paleontological collections occupy the entire first floor of the 

 east wing, of which the large central hall is assigned to vertebrates, 

 the south aisle to invertebrates, and the north aisle to plants. In 

 the last report some account was giA^en of the preparations of fossil 

 vertebrates which had then been completed or renovated, including, 

 among others, examples of the zeuglodon {Basilosaurus cetoides)^ 

 Ceratosavrus nasicornis, C amptosamms hroumi and nanus, a Glaio- 

 smirus, Triceratops prorsus, Trachodon annecfens, an oreodon {Mery- 

 coidodon gracilis), the large mastodon, and the Irish elk. The addi- 

 tions to the hall during last year comprised a skeleton of the short- 

 limbed rhinoceros, Teleoceras fossif/er; remou.nts from the older 

 collection of the cave bear, the toothed diving bird, Hesperornis 

 regalis, and the cast of Pariasaurus; 65 specimens of mammal and 

 fish remains ; a series of limb bones and skulls illustrating the evolu- 

 tion of the horse; a number of ceratopsian and trachydon remains; 

 examples of the more important groups of fossil batrachians, rep- 

 tiles, and birds ; and 20 specimens illustrating the various stages of 

 growth of the common fossil land tortoise, Stylemys nehi^ascensis. 



The general and principal installations in invertebrate paleon- 

 tology comprise a series of specimens illustrating the general condi- 

 tions of sedimentation and fossilization in 1 case; a stratigi'aphic 

 series of specimens occupying an adapted form of American case 

 which extends uninterruptedly along the entire north wall of the 

 hall and is accompanied by a continuous geological section across 

 the North American continent on a scale of 2 miles to the inch; a 

 biological series of fossils in 13 cases distributed through the middle 

 and south parts of the hall; and the I. H. Harris collection of Cin- 

 cinnatian fossils in 2 cases. Among special features are examples 

 .of ripple marks and animal tracks from a Cambrian seabeach; a 

 slab of Uintacrinns with associated fossils, another of Cretaceous 

 crinoids, and a third illustrating near-shore sedimentation. The 

 Springer collection of crinoids has been extensively drawn upon for 

 the exhibits of this section. 



The hall devoted to paleobotany was in a much less advanced con- 

 dition than the others, but contained an extensive series of fossil 

 plants so arranged in stratigraphic sequence as to represent the im- 

 portant plant-bearing horizons, besides a number of large mounted 

 specimens on bases and wall panels. The south wall is used for en- 

 larged drawings and specimens illustrative of special features. 



Speaking of the general arrangement of the exhibition halls, the 

 head curator explains that every effort has been made to provide an 

 open installation, giving the impression of roominess and broad 

 passages. In carrying out this idea, the higher cases have, wherever 

 possible, been placed along the walls and at right angles to the chief 

 sources of light, and the lower cases toward the center of the halls. 



