from the Shales of the Northumberland Coal-field. 277 
determination of its specific and generic relations. From the 
head to the caudal extremity, which appears imperfect, it is 
five and a half inches long, allowing for the sinuosities ; as it 
lies it is about an inch shorter. The head is so much crushed 
that none of its characters can be determined. In its disturbed 
state, however, it is three-tenths of an inch long, and nearly 
two-tenths broad. Thirty-three vertebre can be counted in a 
pretty continuous series extending from the head; they may, 
owever, be estimated at forty. They do not appear to vary 
much in size; the largest are one-tenth of an inch long, and 
they are decidedly hourglass-shaped. The processes cannot 
be determined, though it is pds Be enough that the spinous 
process is not much elevated and that it is shorter than the 
centrum. 
- Numerous rather long, delicate, slightly curved ribs are 
scattered along the sides, from the head almost to the caudal 
extremity. ‘The proximal end is bifid, the capitulum being 
longer than the tuberculum. ‘The ventral shield is distinctly 
displayed ; it extends from about half an inch behind the head 
almost to the other extremity of the body, in the form of a 
broad band, and is composed of very numerous, delicate, 
slightly curved, much elongated scales, with the extremities 
pointed. They are arranged transversely; and the ends of the 
parallel rows overlap each other laterally. 
The extreme delicacy of these scutes, which are almost fila- 
mentous, distinguishes this species from O. Brownriggit, de- 
seribed by Prof. Huxley*. Its diminutive size is also cha- 
racteristic,, No trace of sternal plates or of anterior and pos- 
terior limbs are observable. 
Reptile, species undetermined. 
A single specimen of the central sternal plate of a second. 
large Labyrinthodont was obtained at Newsham some time 
ago. It is nearly five inches long and about three and a 
quarter wide, and is pretty regularly lozenge-shaped, with the 
posterior angle produced, forming a wide, depressed, tapering 
process half an inch broad at the termination, which is trun- 
cate. The sides thence to the lateral angles are a little con- 
cave, and from the lateral angles to the anterior extremity 
(which is not much produced) are slightly convex ; the anterior 
slopes are much shorter than the posterior ones. The surface 
is very rugose, with the usual Labyrinthodont structure, which, 
however, is not so sharply defined as it is in Pteroplaz. 
The depressions and ridges have a radial disposition; the 
* Trans, Royal Irish Academy, vol, xxiv. p. 351, Science (1867). 
