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-tliree vertebraj can be counted in a 

 pretty continuous series extending from the head ; they may, 

 however, 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 evident 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 0. Brownriggii^ de- 

 scribed 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 Fteroplax. 

 The depressions and ridges have a radial disposition ; the 



* Trans. Royal Irish Academy, vol. xxiv. p. 351, Science (1867). 



