Page:Quarterly Journal of the Geological Society of London, vol. 25.djvu/408

310 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 26, cernible upon the slab of shale from Bradford. In all, only the centra are discernible, without any indication of arches or processes. The centra are discoidal, concave on each face, and incline to be somewhat polygonal in contour. They singularly resemble the vertebrae of Anthracosaurus, and, like them, remind one strongly of Ichthyosaurus. The concave face of the largest is 1.4 in. in diameter. In no case can the antero-posterior dimension be made out with accuracy; but it seems not to have exceeded one-third or one-fourth of the transverse diameter. A detached vertebra which, I am informed by Mr. Miall undoubtedly belongs to the fossil, presents a centrum which is quite similar to those scattered about on the slab, together with well-developed articular processes (b, figs. 6 & 7) and remains of transverse processes (a, figs. 6 & 7). The vertebra is much broken, and may have undergone some slight distortion; but its proportions cannot have been very different from those displayed in figs. 6 & 7, and these are very different from those of the vertebrae of Pholidogaster.

The ribs are strong and curved; the largest measures not less than 7 inches along the chord of its arc, while its shaft is 0.3 in. thick. The shortest rib is about 3 inches long, and tapers to a point at its distal end. The proximal ends of the ribs are expanded and divided into two articular facets. No such strong ribs as these are visible in the only known specimen of Pholidogaster; but they are very like the ribs of Anthracosaurus.

The ventral armour of the Bradford fossil consists of scutes (figs. 2, 3, 4, 5), the largest of which are about 2 inches in long diameter, and half an inch across. One end of each scute is rather narrower than the other, and the outer surface of each is traversed obliquely by a convex ridge, which passes from the small to the large end of the plate, and thus divides it into two unequal facets. The facets are occasionally rugose, but are not sculptured; the convex ridge dividing them is smooth. The plates seem to have overlapped one another in such a way as to expose little more than the surface of the oblique ridges; but the precise manner of their arrangement is nowhere shown with clearness in the specimen.

What appear to be remains of the thoracic plates and of the shoulder-girdle are visible, but there are no certain traces of limbs.

I cannot identify this interesting fossil with any generic form at present known. It resembles Pholidogaster more than any genus with which I am acquainted; but it differs therefrom altogether in the form of its vertebral centra, and in the details of its ventral armour.

On the whole, I think it will be best to recognize it as a new generic and specific form, for which I propose the name of Pholiderpeton scutigerum.

Note on the Locality of the Fossil above described. By Louis C. Miall, Esq. [Abridged.]

Fragments of the fossil above described were found last summer in the roof of the Black-Bed or Royd's Coal, at Toftshaw, near Bradford.