102 PROCEEDINGS OF THE NATIONAL MUSEUM. vou55. 



of others), both pubes, both ilia (poorly preserved), sacrum (poorly 

 preserved), and many ossified tendons. 



CERATOPSIAN VERTEBRAE. 



In plate 5, figure 1, is shown an articulated series of eight pos- 

 terior dorsal vertebrae (No. 8091, U.S.N.M.), collected by Messrs. 

 J. B. Hatcher and A. D. Sullins in 1891 on Schneider Creek, Nio- 

 brara County, Wyoming. These vertebrae are notable for their fine 

 state of preservation and that they are from that part of the column 

 of which but little is known at the present time. This series pertains 

 to a member of the genus 2'riceratops, but the species has not yet 

 been determined. 



A DISEASED CERATOPSIAN SCAPULA. 



In plate 6, figures 1 and 2, is shown two views of a Ceratopsian 

 scapula, of the right side belonging to the genus Triceratops, which 

 is of interest on account of the presence on the internal side, of an 

 otherwise normal bone, of a large bony hornlike growth. Fossil 

 bones are often found, and especially of the horned dinosaurs, show- 

 ing fractures that have healed in life (see pi. 9) usually with a 

 considerable enlargement at the point of fracture, but in the present 

 specimen there is no evidence of the bone having been fractured, 

 though this horn-like projection is doubtless an exostosial growth due 

 to pathologic conditions. That it must have been very uncomfort- 

 able to the animal, and a serious handicap to the movement of the 

 shoulder blade, is readily apparent. 



The scapula (No. 8oi3, U.S.N.M.) was collected by the late J. 

 B. Hatcher in 1891 from the Lance formation in Niobrara County, 

 Wyoming. 



RELATIONSHIPS OF CERTAIN CRANIAL ELEMENTS IN THE SKULL. 



During the past few years several papers have been written in 

 which the homologies of the bones of the Ceratopsian skull and brain 

 case have been discussed in considerable detail. While each author 

 has contributed to a better understanding of these elements and their 

 relationships there is still a lack of unanimity of opinion regarding 

 some of them. Certain modifications have led to such a rearrange- 

 ment of the cranial elements that until correctly interpreted are as 

 confusing as they are unusual. The coossification early in life of 

 most of the bones, is another feature that still further adds to the 

 difficulty of determining their true relationships. A restudy of 

 specimens in the United States National Museum in conjunction with 

 two Triceratops skulls recently prepared further elucidate the 



