J. W. HULKE ON POIKILOPLEURON BUCKLANDI. 235 
only in Dinosaurs, and have not yet been found in Crocodiles 
or Lizards. The form of the astragalus is so thoroughly Dino- 
saurian, and so unlike that of Crocodiles and Lizards, that it is 
unnecessary for me to do more than refer to Deslongchamps’s most 
excellent representations of itin pl. vi. fig. 12, and pl. vii. figs. 19-22, 
I believe that the study of these figures of the tibia and astragalus 
cannot fail to convince the reader of his memoir that Poikilopleuron 
is a genuine Dinosaur. These two bones also agree in every 
essential feature with the same bones of Megalosaurus Bucklandi, 
Of the astralagus of Povkilopleuron, Prof. Huxley said, in the paper 
quoted in the list, “ it is altogether like that of Megalosaurus.” 
This statement I would confirm, and I would add that it is easily 
distinguishable from the astragalus of the other European Dinosaurs 
in which this bone has been determined. It is right to add that the 
complete form of the astragalus is at present known only in 
Iguanodon Mantelli, Hypsilophodon Foxui, and Megalosaurus Buck- 
landi. The perfect adaptation of the upper surface of the astra~ 
galus to that of the distal end of the tibia enabled us, however, to 
correctly infer the form of the bone in those Dinosaurs in which it 
is not yet known. The distal end of the tibia of Megalosaurus 
Bucklandi has strong characters which readily distinguish it from 
that of Jquanodon Mantelli, Hypsilophodon Fowit, Hadrosaurus, 
Hyleosaurus, Polacanthus, and Ceteosawrus. The peculiar promi- 
nence and sharpness of the inner lip of the astragaloid depression 
on the antero-external surface at once stamps it as being distinct 
from the tibia of all the Dinosaurs just mentioned, and this stamp 
is only borne also by the tibia of Povkilopleuron. 
With respect to the vertebree, it is unfortunate that Deslong- 
champs’s twenty were all caudal. He writes (p. 75) :—‘ The an- 
terior and posterior faces of the vertebre are slightly concave, and 
the concavity is deeper the nearer the vertebre are to the end of 
the tail.” In the vertebrae of the first series the body is nearly 
circular at the two ends (pl. vii. fig. 14); in the second series it 
more approaches an oval with the larger diameter vertical” 
(pl. vii. figs. 8,9); ‘the border for the attachment of the outer 
layers of the (interarticular) fibro-cartilage is very pronounced.” 
“The middle part of the body differs in the two series; it is 
compressed and rounded in the first series, so as to present not 
more than half the breadth of the two ends. In the narrowest 
part, at the junction of the body, is a wide shallow groove, the 
upper border of which is more prominent in proportion as the 
transverse process springing from it is longer.” ‘ The length 
of the body is to its greatest breadth as 3:2.” “ The body in the 
second series is rather triangular than rounded in the middle, and 
but slightly compressed.” “In both series the body of the ver- 
tebree is hollowed by a large medullary cavity; the spongy tissue 
exists only at the ends.” “ There is at each side in the lateral 
groove a hole for the passage of nutrient blood-vessels.” 
As regards the outward form of the vertebrae, especially in the 
first series, Deslongchamps’s description and figures show a very 
