THEROPODA 423 



tarsals are elongated and fused with each other. There seems 

 to have been some dermal armour in the shape of osseous plates, 

 which extended in one series from the occiput over the neck. 



Coelurus gracilis, of the Upper Jurassic of Wyoming, and 

 closely allied forms in the "Wealden of England, are remarkable 

 for the pneumaticity of the centra and processes of their ver- 

 tebrae, the bony parts of which are restricted to thin, hollowed- 

 out shells, so that the whole skeleton must have been very 

 light. Computed length of these imperfectly preserved creatures 

 about five feet. 



Hallopus victor, of the Upper Jurassic of Colorado. Anterior 

 extremities very short, with only four fingers ; posterior limbs 

 very long and slender, especially the tibia ; the much elongated 

 metatarsals are separate, the first absent, the fifth much reduced, 

 so that the foot is tridactyle ; the calcaneum projects like a heel. 

 The ilium is attached to two sacral vertebrae only ; the pubes 

 are slender, forming a narrow symphysis, while that of the 

 ischia is broad. Most of the bones of this creature, which 

 probably progressed by hops, are hollow. Total length about 

 three feet, the length of the hind-limbs being about nine inches. 



Compsognathus longipes, of the Upper Jurassic of Bavaria, is 

 one of the smallest of all the Dinosaurs. It is most remarkable 

 on account of its almost bird-like feet. The fibula is much 

 thinner and somewhat shorter than the tibia ; the latter is 

 closely attached to, although not fused with the proximal tarsal 

 bones, while the distal tarsals are fused with the united and 

 much elongated second, third, and fourth metatarsals ; the fifth 

 is reduced to a short bone near the iritertarsal joint ; while the 

 first is represented by its distal portion only, which is stowed 

 away on the hinder aspect of the middle of the second meta- 

 tarsal, and carries two phalanges. The three middle toes 

 consist of three, four, and four phalanges respectively. Whilst 

 the whole hind -limb is typically avian, the pelvis is quite 

 different ; the pubic bones are simple, slender, and directed 

 forwards, forming a symphysis with their whole distal halves, 

 and broadening out distally into a horizontal process directed 

 towards the symphysis, which is likewise formed by the fusion 

 of the inner surfaces of the thin and rather flat ischia. The 

 fore -limbs are only half the size of the hind -limbs. The 

 neck consists of about ten vertebrae, mostly with long and 



