624 



PROF. H. Gr. SEELET ON THE REPTILE 



twomus, represented by two species ; the other Dinosaurian genera 

 are Doratodon, Hha dinosaur us, Mochlodon, Ornithomerus, Oligosaurus, 

 and Hoplosaurus. 



Condition of the Specimens. 



Almost all the bones are in fragmentary condition, and somewhat 

 distorted by the effects of pressure. Being hollow, they have some- 

 times become greatly crushed ; and were it not that both right and 

 left bones are usually preserved, it would often be difficult to avoid 

 being misled by appearances which result from conditions of fossili- 

 zation. Unfortunately almost all the long bones have lost their 

 articular extremities, and although in some instances this may 

 perhaps be the result of fracture, yet in most cases it is certainly a 

 consequence of decay of the bones before they were covered up in the 

 deposit. I do not speculate as to whether the articular ends may 

 have been eaten off by large carnivorous contemporaries ; for there 

 are no indications of tooth-marks or other evidences of animals 

 which might thus have mutilated the specimens. No doubt to some 

 this condition would be proof that the remains were derived from 

 an older deposit ; but since the Wealden and Cambridge Greensand 

 and Stonesfield Slate all have a number of bones in a not dissimilar 

 condition, it seems to me less hypothetical to find an explanation 

 of their condition in prolonged maceration, coupled with the litho- 

 logical and petrological modifications which the deposit has since 

 undergone. There is, however, no record of natural association of 

 any of the remains ; yet, as they have mostly come from the same 

 locality, it is probable that remains which agree in size and anato- 

 mical characters may, in most cases, with certainty be referred to 

 the skeleton of the same individual, since duplicate parts of the 

 skeleton are almost unknown in each species. There may perhaps 

 be a certain amount of doubt as to the correct association of the 

 remains which I have ventured to put together ; but this is a doubt 

 which the anatomist will best appreciate who can realize the nature 

 of the studies which have led me to group the bones as here set 

 forth. 



Mochlodon Stjessii (Biinzel). (PI. XX.VIL fig. 1.) 

 See Biinzel, I. c. p. 8, pi. iii. figs. 7-11. 



One of the most beautifully preserved specimens is a right dentary 

 bone of a small Dinosaur which at first sight exactly reproduces in 

 miniature the characters of the Iguanodon of the Weald ; but it 

 differs in a character so remarkable that, had it occurred in a living 

 animal, no hesitation would have been felt in relegating the jaw to 

 a distinct genus. Anterior to the teeth, the symphysial extremity 

 of every Iguanodon-j&w bends round so that the rami form a U- 

 shaped curve ; but this specimen is straight, and the anterior inward 

 inflexion is scarcely appreciable, so that the snout was evidently 

 sharply pointed, and therefore indicative of a new form of head. 

 The fragment is little more than 1\ centimetres long, and the tooth- 

 bearing part of the jaw 17 or 18 millimetres; the height at the 



