568 SCIENCE PROGRESS 



legs straddled considerably." Further remarks on this subject 

 are recorded in the sequel. 



One of the most interesting discoveries recorded during the 

 year is that of what may truly be termed a dinosaur-mummy. 

 As described by Prof. H. F. Osborn in the American Museum 

 Journal for January 191 1, the remains in question are those of a 

 giant reptile from the Laramie Cretaceous of Wyoming which 

 include not only the greater part of the skeleton but likewise 

 the skin, which is tightly drawn over the bones. Other 

 specimens have been obtained from the same formation in 

 which portions of the skin are retained ; but this is the only 

 one in which nearly the whole is preserved, although its 

 describer is of opinion that if due care had been taken in 

 their extraction from the matrix several other skeletons would 

 also have shown the dermal covering. This reptile, which 

 stood from 15 ft. to 16 ft. in height, with a total length of about 

 30 ft., is known as the duck-beaked dinosaur, on account of the 

 great lateral expansion of the toothless extremities of the jaws. 

 Not that the creature was altogether toothless, for the sides of 

 the jaws are armed with a pavement-like arrangement of flat- 

 crowned grinding teeth recalling those of the iguanodons of the 

 English Wealden but of a more specialised type. The skin of 

 this reptile {Trachodon insignis), for an illustration of which 

 I am indebted to Prof. Osborn, was covered with granules or 

 tubercles, varying in size in different parts of the body, of which 

 the impressions are perfectly preserved. Prof. Osborn is of 

 opinion that the carcase of the reptile lay for some time after 

 death on the banks of a river millions of years ago, where it was 

 subject to the rays of a scorching sun until converted into a 

 mummy. A flood probably then carried the desiccated carcase 

 down-stream till it reached a point where it was retained and 

 quickly buried beneath a mass of clayey sand sufficiently stiff to 

 show the impression of the surface of the skin. The specimen 

 also shows that the short fore-limbs, instead of having claws, 

 were flattened out and covered with skin, so as to form a kind of 

 paddle-like structure. In addition to showing a pattern in the 

 size of the tubercles, the skin probably also exhibited a colour- 

 pattern, so that from the analogy of lizards and snakes it is not 

 unlikely that these giant reptiles presented a darker appearance 

 when seen from in front than when viewed from behind. The 

 position where the skeleton was found, coupled with the paddle- 



