A Retrospect of Palceontology for. Forty Years. 147 



especially to the Dinosaiiria. In 1882 he proposed a classification 

 of the Dinosauria which (with some modifications) is still followed 

 by pal^ozoologists. 



In the same year this author discussed the wings of Pterodactyls, 

 basing his remarks on the specimen discovered at Eichstadt, Bavaria, 

 'in 1873. This long-tailed form, named Bhamphorhynchus phyllurus 

 by Marsh, has both the wing membranes preserved, and shows that 

 the long stiff tail had a broadly expanded extremity like the blade 

 of a paddle, which was evidently used as a rudder. We have 

 a similar form named Dimorphodon, which was obtained from the 

 Lias of Lyme Regis (see 1870, p. 97, PI. IV). In 1884 Marsh 

 figured and described the skull of the great toothless American 

 Pterodactyl from the Chalk of Kansas (named Fteranodon), with 

 a skull a yard in length, and wings having an expanse of about 

 18 feet across ! — as large as our great toothed Pterodactylus Cuvieri 

 and P. giganteus from the English Chalk of Durham, Kent. 



He also (1884) named Diplodocus longiis,a new Jurassic Dinosaur, 

 from Caiion City, Colorado, giving figures of the skull, teeth, etc. 

 It possessed one of the most remarkable heads of this singular group 

 of land reptiles and the weakest possible dentition, the teeth being 

 entirely confined to the front of the jaws and of simple slender 

 peg-like form, and they must have been easily detached from their 

 shallow sockets. The nasal opening was at the apex of the cranium, 

 and the brain was of the very smallest dimensions possible. 



Then followed an account, with figures, of various other new 

 forms of Jurassic Dinosaurs — Allosaurus, CoBlurus, Lahrosaurus, and 

 Geratosaurus. These were all carnivorous forms (Theropoda), the 

 last-named being near to our own Megalosaunis, the teeth and 

 claws both displaying their predaceous character. Allosaurus had 

 extremely diminutive fore-limbs and long slender hind ones, adapted 

 evidently for springing upon its quarry. 



Passing from these lithe and active beasts of prey, we come 

 (in 1888) to one of quite another character, namely, Marsh's 

 Stegosaurus, a huge plated lizard of the Jurassic period. It had 

 the smallest brain of any known land vertebrate. All its bones 

 were solid, the vertebrge biconcave. Its body was defended by 

 a row of twelve flattened dorsal bony plates, the largest being 

 nearly four feet in height and of equal length ; with four pairs 

 of sharply pointed spines fixed erect like bayonets on the caudal 

 vertebrae. A restoi'ation was given by Marsh of this huge herbivore 

 in 1891. 



A further comparison of the principal forms of Dinosauria of 

 Europe and America was given by Marsh in 1889, in which he 

 defined the group Sauropoda or lizard-footed forms. Many of 

 these are known in Europe as well as America, but here they are 

 more fragmentary. A large part of one has just been set up from 

 the Oxfordian of Peterborough, whilst limb-bones of Cetiosaurus (as 

 large as those o? Atlantosaurus) may be seen in the Oxford Museum 

 and in the British Museum (Natural History), London. The section 

 Stegosauria is represented by Omosaurus, from Swindon; Hylfso- 



