R. W. Hooley — Integument of Wealden Dinosaurs. 149 



of Fig. 1 are also decidedly larger and flatter than the others. One 

 plate-like tubercle, 10 mm. in diameter, occurs on the smaller 

 portion of the skin from the same inguinal region. It appears 

 therefore probable that on those parts of the body exposed to the sun 

 large flat tubercles would be found as in Trachodon anneetens, 1 and it 

 is evident that the "ground plan" of the epidermis is essentially 

 similar, consisting of small, rounded tubercles, although in Iguanodon 

 they are not so rounded or apical. Professor Osborn l thought that 

 the iguanodonts from the Lower Cretaceous of Europe would probably 

 be distinct in their " epidermal covering " from the trachodonts of the 

 Upper Cretaceous of America, and it is interesting to find that at 

 least they are alike in ground plan. 



Integument oe Morosaurus beoklesii, Mantell = M. brevis, Owen. 



An impression of the epidermis of this reptile (Fig. 2) is well 

 displayed on a block of rock removed from the hollow between the 

 radial crest and the inner border of the left humerus. This humerus, 

 with the radius and ulna, was found in the Wealden beds of 

 Hastings by S. H. Beckles in 1852. These specimens (No. It. 1870) 

 are now in the British Museum. They were referred to by Mantell 

 in a lecture given by him at the Royal Institution in that year. 

 The report 2 of the lecture records that " A portion of the scaly 

 cuirass which covered the limbs and is composed of hexagonal plates 

 was exhibited". The integument was also noticed by Marsh, 3 when 

 examining this fossil while still in the possession of its discoverer. 

 He remarks that he "found attached to the humerus portions of the 

 osseous dermal covering, the first detected in the Sanropoda, and 

 known only in the present specimen". It has not been further 

 described, but by kind favour of Dr. A. Smith Woodward I am now 

 privileged to give the details. 



The side of the matrix upon which the epidermal markings are 

 shown is convex, well seen in Fig. 2, but this feature is entirely due 

 to the concavity of the particular area of the humerus upon which it 

 lay and not to the natural rotundity of the limb. There was no 

 intervening matrix between the skin impression and the bone, 

 therefore unless this portion of the integument was turned inside out 

 after the decomposition of the muscles and before the matrix was 

 deposited upon it, the under surface of the epidermis is exhibited. 

 The only fact that supports the improbable theory of the reversal of 

 the integument is that there is an apparent ornamentation of very 

 small rounded tubercles displayed on some of the plates. The 

 smallest plates, especially at the upper end of the specimen, are 

 covered with them. It does not appear that they are due to 

 oxidization subsequent to the removal of the block from the humerus. 

 I have observed a somewhat similar result from chemical action after 

 exposure to the atmosphere on matrix which at first had a smooth 

 surface. However, it is more probable that they are papilliform 



1 H. Osborn, Mem. Amer. Mus. Nat. Hist., N.S., vol. i, pt. ii (June, 1912), 

 pp. 46, 47. 



2 Proc. Eoy. Inst., vol. i, p. 34, 1852. 



3 0. C. Marsh, Geol. Mag. [3], pp. 205, 206, 1889. 



