COELURID^. 155 



pelvic ; scapula expanded proximally, with concave anterior border ; 

 coracoid with descending process ; humerus usually with head im- 

 perfectly differentiated from tuberosities ; terminal phalangeals of 

 manus long, curved, and compressed. Ilium (fig. 25) deep, with 

 superior border usually greatly arched, and short preacetabular and 

 long postacetabular process ; pubis directed downwards and for- 

 wards, with an antero-posteriorly expanded bony symphysis, and, 

 at least usually, a considerable osseous union of the lower part of 

 the anterior border, which consequently resembles an elongated Y ; 

 ischium comparatively slender and of moderate length, usually 

 with an obturator process. Femur usually with inner trochanter, 

 curved shaft, and of a more or less Crocodilian type, slightly longer 

 or shorter than tibia; astragalus applied to tibia; metatarsals 

 elongated ; terminal digits of pes short and rounded ; feet 

 usually digitigrade. The more specialized members were of bipedal 

 habits. 



Seeley 1 has proposed to unite the present with the preceding 

 Suborder, under the name of Saurischia, and to regard this larger 

 group as an Order. 



Family CCELURID^. 



Vertebrae completely hollowed, as in the presacral series of the 

 Sauropoda ; cervicals opisthocoelous, longer than dorsals, with 

 anchylosed ribs and no neural spines ; sacral arches probably sup- 

 ported by single vertebrae. Anterior bony union of pubis much 

 elongated. Skull unknown. 



In the structure of the vertebral column this family closely 

 resembles the Sauropoda ; it appears connected with the Megalo- 

 sauridce by Aristosucluis. 



Genus CCELTJRUS, Marsh 2 . 



The type genus. In allied Triassic forms referred by Cope 3 to 

 Tanystroplmus, there are four vertebra3 in the sacrum, and the 

 femur has no distinct inner trochanter. All the species were of 

 comparatively small size. 



1 Eep. Brit, Assoc, for 1887, p. G99, and Proc. R. Soc. vol. xliii. p. 171 (1887). 



2 Amer. Journ. ser. 3, vol. xviii. p. 504 (1879). 



3 Amer. Nat. vol. xxi. p. 367 (1887). and Proc. Arner. Phil. Soc. vol. xxiv. 

 p. 221 (1887). 



