72 Royal Institution :-— 
the vertebral column completely known, while the sternum and the 
manus have not yet been obtained in any of the genera. In none 
has any trace of a clavicle been observed. 
With regard to the characters which have been positively deter- 
mined, it has been ascertained that :— 
1. From four to six vertebre enter into the composition of the 
sacrum, and become connected with the ilia in a manner which is 
partly ornithic, partly reptilian. 
2. The ilia are prolonged forwards in front of the acetabulum as 
well as behind it; and the resemblance to the bird’s iium thus pro- 
duced is greatly increased by the widely arched form of the acetabular 
margin of the bone, and the extensive perforation of the floor of the 
acetabulum. 
3. The other two components of the os nnominatum have not been 
observed actually in place ; indeed only one of them is known at all ; 
but that one is exceedingly remarkable from its strongly ornithic 
character. It is the bone which has been called “clavicle” in Me- 
galosaurus and Iguanodon by Cuvier and his successors, though the 
sagacious Buckland had hinted its real nature *. But these bones 
are not in the least like the clayicles of any animal which possesses 
a clavicle, while they are extremely similar to the ischia of such a 
bird as an ostrich’; and in the only instance in which they have been 
found in tolerably undisturbed relation with other parts of the ske- 
leton, namely, in the Maidstone Jguanodon, they lie, one upon each 
side of the body, close to the ilia, I hold it to be certain that these 
bones belong to the pelvis, and not to the shoulder-girdle, and I 
think it probable that they are ischia; but I do not deny that they 
may be pubes. 
4. The head of the femur is set on at right angles to the shaft of 
the bone, so that the axis of the thigh-bone must have been parallel 
with the middle vertical plane of the body, as in birds. 
5. The posterior surface of the external condyle of the femur pre- 
sents a strong crest, which passes between the head of the fibula and 
the tibia as in birds. There is only a rudiment of this structure in 
other reptiles. 
6. The tibia has a great anterior or “ procnemial” crest, convex 
on the inner and coneaye on the outer side. Nothing comparable to 
this exists in other reptiles; but a correspondingly developed crest 
exists in the great majority of birds, especially such as have great 
walking or swimming powers. : 
7. The lower extremity of the fibula is much smaller than the 
other ; it is, proportionally, a more slender bone than in other rep- 
tiles. In birds the distal end of the fibula thins away to a point, 
and it is a still more slender bone. 
8. Scelidosaurus has four complete toes, but there is a rudiment of 
a fifth metatarsal. The third or middle toe is the largest, and the 
* The so-called “coracoid” of Megalosawrus is the ilium. Iam in- 
debted to Professor Phillips, and to the splendid coilection of Megalosau- 
rian remains which he has formed at Oxford, for most important evidence 
touching this reptile. 
