228 



REPTILIA 



In the pectoral arch the scapula is longer and stouter than the humerus, 

 the coracoid is more or less crescentic or semicircular, and there is no ossified 

 sternum. The fore -limbs are small, the carpus is, as a rule, incompletel)^ 

 ossified, and the clawed digits are of only moderate size. In the pelvic arch 

 the ilium is low and antero-posteriorly extended, the post-acetabular portion 

 lower and more elongated than the pre-acetabular, and the acetabulum itself 

 is perforate. Both the pubes and ischia meet in ventral symphyses, which are 

 often much extended, and apparently served as a support for the body when 

 in a crouching or sitting position. The structure of the inassive hind limbs 

 indicates that progression was mainly bipedal and digitigrade. The proximal 

 tarsals tend to form a tibio-tarsus, and in most genera the astragalus bears an 

 ascending process, which is immovably applied against the anterior face of the 

 tibia, as in young ostriches. Theropoda first appear in the Trias, and become 

 extinct in the Cretaceous. 



Family 1. Meg-alosauridae. Huxley. 



Vertebrae solid and amphiiylatyan, except the cervical s, lohich .are opisthocoelous. 



Piibes long, projecting simply downvjards and forwards, and united in an extended 



ventral symphysis. Extremities 2)entadactyl, but the inner 



and outer digits frequently rudimentary. Trias to 



IJpjDer Cretaceous. 



Zandodon, Plien. [Plateosaurus, Teratosaurus, 

 Smilodon, v. Meyer ; Gresslyosaurus, Eiitim.). Teeth 

 with serrated anterior and posterior cutting edges. 

 Vertebral column comprising at least sixty vertebrae, 

 three of which are sacral. Limb bones stout. 

 Keuper ; Wilrtemberg. Z. laevis, Plieninger. 



Dimodosaurus, Pidancet and Chof. Keuj^er ; 

 Poligny, France. Cladyodon, Owen ; Thecodo)dosaurus, 

 Fcdaeosaurus, Riley and Stutch. Trias ; Bristol, 

 England. Rachiirema, Sauvage. Ehaetic ; Autun, 

 France. Epicarnpiodon, Huxley. Trias ; East India. 

 Euscelosaurus, Huxley. Trias ; South Africa. These 

 ai-e imperfectly known genera allied to Zandodon. 



Anchisaurus, Marsh (Fig. 327). Skull remark- 

 ably bird-like, with very large orbits and antorbital 

 vacuit\^ ; narial oi3ening relatively small ; supra- 

 temporal vacuity subrectangular. Quadrate inclined 

 steeply forwards. Teeth numerous, nearly uniform, 

 and closely set. Fore -limb about two -thirds as 

 large as the hinder pair, with only three clawed 

 digits, the fourth and fifth rudimentary. In the 

 pes the fifth digit is reduced, and the first much 

 shorter than the rest. Total length slightly exceed- 

 ing 1 m. Trias ; Connecticut. 



Armnosaurus, Marsh ; Bathygncdhus, Leidy ; Arcto- 



saurus, Adams ; Clepsysaurus, Lea. Represented by fragmentary remains from 



the Trias of Xorth America. 



Ceratosaurus, Marsh (Figs. 328, 329). Skeleton 4-5 m. long, skull 



.'1 nch i saurus major, Marsh. 

 Trias ; Manchester, Conn. 1/4. 

 Dorsal aspect of right liind foot. 

 a, Astragahis ; v, Calcaneuin ; /', 

 Fibula; /, Tibia; f..-*4, Distal 

 tarsals ; I— V, Digits (alter Marsh). 



