466 
PEOFESSOE OWEN ON THE DICYNODONT EEPTILIA. 
PLATE XXIV. 
Fig. 3. Back view of sacruni and pelvis : ^ nat. size. 
Fig. 4. Os innominatum, inner surface : nat. size. 
The outline restored by dots, where abraded. 
(HI.) Notice of a Skull and ^arts of the Skeleton of Bhynchosatjkus aeticeps. 
By Professor Owen, F.B.S. &g. 
The rocks in South Africa containing the Dicynodont Eeptilia, appear, by other fossils, 
especially of some plants, to belong to the Triassic period. It is in the New Bed Sand- 
stones of Europe and of our own island, that reptilian remains have been discovered 
which offer the nearest approach, though the gap is wide, to the dicynodont type. 
A lizard which, in biting, with trenchant edentulous jaws, may also have pierced its 
prey by a pair of produced weapons analogous to the tusks of JDicynodon, has left its 
remains in the New Red Sandstone of the Grinsill quarries near Shrewsbury. In this 
singular species {Bhynchosaurus artice^s*) the premaxillary bones, by their shape and 
structure — the bony tissue of the produced tips acquiring the hardness and almost the 
texture of dentine — and by the production of their sharp end (Plate XXY. fig. 2, 22'j 
beyond the mandible {ib. 32), may have inflicted wounds and served a piupose, like those 
of the upper curved tusks of the Bicynodon. 
I take the present opportunity of briefly noting a second example of this exceedingly 
rare fossil reptile, found, like the first, in the Grinsill sandstone, and liberally trans- 
mitted to me for examination and description by the Directors of the Museum of Natu- 
ral History at Shrewsbury. This fossil consists of the skull almost entire (Plate XXV. 
figs. 1 and 2), with about fifteen of the anterior vertebrae {ih. figs. 3 and 4) more or less 
mutilated; and in the same slab of stone are parts or impressions of seveaul ribs, a 
humerus {ib. fig. 3, 53), antibrachial {ib. 54, 55) and metapodial {ib. n) bones. All these 
parts agree sufiiciently in size and other characters with the first-discovered specimen to 
be referable to the same species. 
The apparent greater breadth of the cranium is due to its having been crushed almost 
fiat (fig. 1), which has correspondingly expanded the mandibular rami (fig. 3, 31, 31); but 
the force has been applied either so gradually, or, whether gradually or suddenly, with 
such equable support from the surrounding matrix, that there has occurred little ffactui-e 
or dislocation. 
The temporal muscles have encroached upon the sides of the parietal (fig. 1, 7), so as 
to develope a straight median crest along that bone. The outer and back part of the 
temporal fossa is bounded by a strong triangular mastoid {ib. s), which unites by an 
oblique suture with the long postfrontal, 12. The prefrontals are seen at u in fig. 1. A 
portion of the lower or true zygomatic arch, not preserved in the first specimen, is 
* Transactions of the Cambridge Philosophical Society, vol. vii. 
