July 27, 1893] 



NA TURE 



O'-'J 



scarcely be said, by the generally bird-like arrangement of the 

 pelvis, in which the front part of the ilium is much produced 

 forwards, while the pubis has its main shaft («hen present) 

 directed backwards alongside of the ischium in a bird like 

 fashion (Fig. 3), and also giving off an anterior process which 

 must not be confounded with the main shaft of the pubis of the 

 Brontosaur (Fig. i). The bird-footed Dinosaurs are subdivided 

 into the armoured and the typical sections, of which the former 

 has but lately been fully made known to us. 



As our first example of the former, we lake the skeleton 

 of the Jurassic Hypsirophus represented in Fig. 3. The exist- 

 ence of this type of Dinosaur was first revealed by the discovery 

 in 1875 of a considerable portion of a skeleton (now in the 

 British Museum) in the Kimeridge clay of Swindon, which was 

 described by Sir R. Owen during the same and following years 

 under the name of Omosaurus ; — a term which unfortunately 

 proved to be a preoccupied one. This skeleton comprised many 



of a most marvellous monster. The Professor tells us that this 

 restoration is based on a specimen which " had the skull, 

 skeleton and dermal armour together when entombed, and 

 almost in the position they were when the animal died. . . . 

 In this restoration the animal is represented as walking, and the 

 position is adapted to that motion. The head and neck, the 

 massive fore-limbs, and, in fact, the whole skeleton indicate 

 slow locomotion on all four feet. The longer hind limbs and 

 the powerful tail show, however, that the animal could thus 

 support itself as on a tripod, and this position must have been 

 easily assumed in consequence of the massive hind-quarters. 

 . . . . The neural sp nes of the vertebras have their summits 

 expanded to aid in supporting the massive dermal armour above 

 them. The limb-bones are solid, and this is true of every other 

 part of the skeleton. The feet were short and massive, and the 

 terminal phalanges of the functional toes were covered by strong 

 hoofs. There were five well-developed digits in the fore foot, 



Fig, 2. — Restoration of a skeleton of a CAfnivorous D.nosaur, ,',. natural size. (After Marsh.) 



of the vertebr;e and limb-bones together with some long spines 

 •■imilar to those represented at the end of the tail in Fig. 3. 

 The skull is, however, missing, and there are no traces of the 

 huge plates of bone shown in the restoration. If, however, we 

 imagine the body of the reptile to which this skeleton pertained 

 to have been drifting in the water sufficiently long to have lost 

 its head by the action of decomposition, there is nothing more 

 probable than that the row of plates along the back should have 

 likewise disappeared. From 1877 onwards Prof. Marsh has 

 been gradually completing our knowledge of allied reptiles from 

 the upper Jurassic of Colorado and Wyoming, to which he 

 applied the name Slegosaurus, but which appear to have been 

 previously described by Prof. Cope under the title of Hypsiro- 

 phus. First we had descriptions of some of the vertebras and 

 liml)- bones, with isolated specimens of the plates and spines of 

 the armour ; then we had the head ; and finally we are favoured 

 with the restoration shown in the figure, which is certainly that 



NO. 1239. VOL. 48] 



and only three in the hind foot, the first toe being rudimentary, 

 and the fifth entirely wanting." 



" In life the animal was protected by a powerful dermal 

 armour, which served both for defence and offence. The 

 throat was covered by a thick skin, in which was embedded a 

 large number of rounded ossicles, as shown in the figure. The 

 gular portion represented was found beneath the skull, so that 

 its position in life may be regarded as definitely settled. The 

 series of vertical plates extended above the neck, along the 

 back, and over two-thirds of the tail is a most remailiable 

 feature, which could not have been anticipated, and would 

 hardly have been credited had not the plates themselves been 

 found in position. The four pairs of massive spines character- 

 istic of the present species, which were situated above the 

 lower third of the tail, are apparently the only part of this 

 peculiar armour used for offence. In addition to the portions 

 of armour above mentioned, there was a pair of small plates 



