650 



PROF. H. G. SEELEY ON THE EEPTILE 



flattened they maintain a remarkable uniformity of width, and taper 

 almost imperceptibly towards the distal extremity. 



Dermal Armour. 



(See Biinzel, pi. iv. figs. 1, 2, pi. vii. figs. 20, 21, pi. viii. figs. 9-12.) 



The Dinosaurian dermal armour which I refer to the genus 

 Cratceomus presents many remarkable modifications, such as have 

 not been met with in any genus hitherto described. Some of the 

 plates are remarkably similar to those of JScelidosaurus and Acan- 

 thopholis ; others are large scutes with a median longitudinal ridge 

 and numerous vascular impressions on the carinate surface, as 

 though they were imbedded in the skin. These plates are all 

 thin and may have been abdominal, while the more elevated plates 

 may have been dorsal and caudal. A third type of plate appears 

 to be greatly compressed from side to side with a sharp cutting 

 surface in front, terminating in a spike superiorly, and with a 

 rounded posterior margin. The articular bases of these plates are 

 not preserved. A fourth kind of plate of large size appears to have 

 terminated at each end in a great triangular spike, while across the 

 intermediate space there extended rows of conical tubercles some- 

 what resembling in outline those attributed to Hylceosaurus. A fifth 

 kind of armour is represented by an immense conical spine, like the 

 horn- core of an ox, which rises from a bony base. 



None of these pieces of armour are symmetrical, hardly any of them 

 can be grouped in pairs ; altogether there are fully fifty well-defined 

 plates, besides a large number of fragments. It is quite possible 

 that the remains may have belonged to more than one species. But 

 seeing that the vertebral column of one species is well preserved in its 

 hinder portion, and that to this species the bulk of the limb bones may 

 reasonably be relegated, and that in many points of osteology there 

 is an approximation of the animal towards Scelidosaurus, we may 

 be justified in considering that the larger Austrian Dinosaur possessed 

 armour as varied in character as that seen in its English prototype ; 

 and in the absence of a second and larger vertebral column, I am 

 unwilling to attempt to divide the scutes between the two different 

 animals, merely on the ground of their contours. Yet it may be 

 acknowledged that the horncore-like scute is larger than would 

 have been expected, and that the whole armour is heavy even 

 for an animal with such strongly marked muscular development as 

 is shown on the bones of the limbs of both the species. 



I proceed to describe the armour according to the varieties it 

 presents. As Prof. Suess had noticed, there is, besides the horn- 

 like scute, a second base, from which the horn-like spine has been 

 broken away. There thus appear to have been at least a pair. 

 The base from which the horn rises (PI. XXVIII. fig. 4) is 5| inches 

 long, of irregular oblong shape with roughened edge, a little 

 broken at one end. It is nearly 3| inches wide where widest, 

 and narrows to about 2| inches. It is concave in length on the 

 under surface in the middle, convex at the sides. The margin is 

 full of vascular perforations, and appears to have had strong union 



