BOTHRIOLEPIS OBESA. 121 



The same specimen placed horizontally and seen from the outer side is shown 

 in Pig. 4. Here we have a view of the ascending lamina of this posterior ventro- 

 lateral plate, which is seen to be proportionately higher than in B. major. The 

 external ornament is here almost completely gone. 



In Fig. 5 we have a view of the right posterior dor so-lateral plate from which, 

 unfortunately, the greater part of the outer surface has been lost, so that only the 

 faintest traces of external sculpture are seen. Its high and broad contour may be 

 noted, as well as the narrow area in front, where it is overlapped by the anterior 

 dorso-lateral, above which, and along the anterior part of the upper margin, is an 

 internal impression of the arm, which overlaps the anterior median dorsal. 



In PI. XXVII, Fig. 1, is represented a specimen of the anterior median dorsal 

 plate. It is, unfortunately, a " bad " specimen, as it wants the posterior extremity 

 and is also considerably broken away along the sides, besides which most of the 

 bony material of the plate is gone. The outlines of the areas on each side over- 

 lapping the anterior dorso-lateral plates clearly indicate the genus Bothriolepis, 

 while the elevated form of the plate, distinctly carinate posteriorly, is in marked 

 distinction to the condition in B. major. 



The internal surface of this plate (anterior median dorsal) is shown in Fig. 2, 

 PI. XXVII, taken from a plaster mould. Comparing this with the corresponding 

 view of the same plate in B. major (PI. XXIV, Fig. 2), we find a general agree- 

 ment as to outline and markings, with a very decided difference in this respect, 

 that while in the latter the surface is much flattened, in the present plate it is 

 deeply hollowed longitudinally, the hollow indicating, of course, a corresponding 

 longitudinal elevation or carina, of the middle of the outer surface. 



Turning now to the remaining specimens, which are from Harelaw, near Chirn- 

 side, in Berwickshire, we find that they exist only as impressions on the stone, 

 a coarse, deep brick-red sandstone, and consequently the figures here given of 

 them are taken from plaster moulds, as in the case of most of the plates of B. major 

 from Alves. Fig. 3, PL XXVII, represents a broken anterior median dorsal plate 

 showing marked carination behind the central point, and a sculpture resembling 

 that of H. major. Posteriorly, part of the area overlapped by the posterior median 

 dorsal is observable. In Fig. 4 we have a left posterior dorso-lateral plate, which, 

 however, unfortunately wants a considerable portion above and in front. The 

 longitudinal carina dividing the dorsal from the lateral surface is here prominently 

 developed, the lateral sensory groove being seen a little way under it. All the 

 articular areas of the outer surface of this plate in Bothriolepis arc seen — namely, 

 one above and behind, overlapped by the posterior median dorsal, an extensive one 

 below overlapped by the ascending lamina of the posterior ventro-lateral, and 

 another in front overlapped by the anterior dorso-lateral. 



Fig. 5 represents a portion of the plates of the upper arm, seen from the inside, 



