G. F. Eaton — Characters of Pteranodon, 85 



paleontologists. Three diagrams of this specimen are here 

 given, showing the side, top, and bottom views (Plate YII, fig- 

 ures 1, 2, and 3, respectively). It is not mj intention at this 

 time to enter into a detailed description of the pelvic charac- 

 ters. Indeed, at present, it is necessary to publish little more 

 than the diagrams, which may prevent any further serions 

 misinterpretation of the pelvis. 



Ten vertebrse firmly anchylosed together form the sacral 

 series, using this term in its broader sense. The upper ends 

 of the neural spines of all these vertebrae are united in a con- 

 tinuous ridge about 9™™ wide and about 6°"°" in vertical depth 

 (Plate YII, figure 1). The general form of the transverse pro- 

 cesses of the three anterior vertebrae in this series, and their 

 union with the ilia, are sufiiciently well shown in the accom- 

 panying diagrams (Plate YII, figures 2 and 3). The first verte- 

 bra bears anterior zygapophyses for articulation with the last 

 free dorsal; and the transverse processes of the first three 

 vertebrae have on their lower surfaces small facets for the sup- 

 port of ribs. One of these posterior ribs still lies upon 

 the third vertebra, with little displacement from its original 

 position. The transverse processes of vertebrae 4, 5, 6, and 7, 

 depart widely from the foregoing simple arrangement. They 

 are likewise separated by large foramina, but they unite again 

 laterally and form a continuous support for the ilia. The 

 lower ends of the transverse processes of vertebra 4 extend 

 downward and backward, as stout buttresses, finally becoming 

 confluent mth the inferior margins of the ilia. The three 

 remaining vertebrae, numbers 8, 9, and 10 of this series, bear 

 short transverse processes, separate at their distal ends, upon 

 which the ilia rest posteriorly. 



The ilia extend forward as broad, thin blades, supported, at 

 their inner margins, by the transverse processes of the anterior 

 sacral vertebrae. Posteriorly they unite over the neural spines 

 of the last three sacrals, and are anchjdosed to them as well as 

 to the transverse processes. The united pubes and ischia are 

 directed downward and backward, and meet below in a long 

 median symphysis. The obturator foramina lie just beneath 

 the imperforate acetabula. They are circular in form, of about 

 half the diameter of the acetabula, and may be considered as 

 marking the theoretical line of fusion between the true pubic 

 and ischial elements. On the anterior border of these ischio- 

 pubic expansions are small facets, which undoubtedly served 

 for the attachment of prepubes. In no specimen in the Yale 

 Collection has a prepubis yet been found in place. 



Paleontologists will perhaps disagree on the number and 

 position of true sacrals in Pteranodon. It will be remem- 

 bered that Huxley, when confronted with a similar problem in 



