234 



DR. A. SMITH WOODWARD ON 



vertebral centra. There is thus the common diplospondyly. The 

 vertebral arches are scarcely seen, except within the caudal fin, 

 which is displayed in direct side-view. Here the hremals are 

 apparently stouter and less inclined backwards than the neurals. 

 The pectoral arch is only imperfectly shown, but the right 

 pectoral fin is complete- It is relatively large, and the supporting 

 cartilages extend only about half-way from its insertion towards 

 the distal margin. The three basals are distinct, the propterygium 

 being comparatively small and narrow, the triangular meso- 

 pterygium about rts wide as long, and the metapterygium longer 

 than wide but very little produced backwards. The radial 

 cartilages, which are not much longer than the basals, are rather 

 sparsely arranged and do not clearly exhibit any transverse 

 articulations. About 12 are arranged along both the mesoptery- 

 gium and the metapterygium. Faint striations are seen in part 

 of the fin-membrane, but there are no distinct remains of dermal 

 rays. The pectoral fins extend as far backwards as the pelvic 

 fins, which are much smaller. The pelvic basipterygium is long and 

 gradually tapering, and bears at least 17 radial cartilages, which 

 (like those of the pectoral) are not closely pressed together and do 

 not show any transverse articulations. The cartilages occupy only 

 half of the total expanse of the fin. As they are imperfect behind, 

 the sex of the individual is uncertain. Of the median fins, one large 

 dorsal, bordered in front by the remains of a smooth, laterally 

 compressed spine (cl l ), arises just behind the origin of the pelvic 

 fins; but it is very imperfectly preserved. The impression of the 

 fin-membrane shows some fine striations, which may perhaps 

 denote strengthening dermal rays. As the tail of the fish is 

 relatively long, this is doubtless the first dorsal fin, but the fossil 

 is too fragmentary to exhibit the second dorsal. The caudal fin, 

 which is displayed in direct side-view and only incomplete at the 

 upper extremity, is long and ovoid, with the lower lobe the larger. 

 The membrane here again shows faintly some fine striation. Just 

 in advanpe of its lower lobe, a small deep and narrow fin is shown 

 (a.), with most of the outline defined by oxide of manganese. 

 Though its separation from the caudal is a little obscured by the 

 rough fracture of the rock, it is almost certainly distinct and may 

 be regarded as an anal fin. Fine shngreen covers the whole of 

 the trunk and fins. Near the margins it is especially smooth and 

 dense, but on parts of the trunk the granules are rather stellate. 

 On the trunk in front of the pectoral fins, and again on the 

 tail just behind the pelvic fins, it is interesting to notice that the 

 course of the lateral line is marked by a close series of incomplete 

 ringlets (fig. 2a), as in Chimseroids and in the extinct dog-fish, 

 Mesiteia. 



Young Specimen. — A second specimen in the British Museum 

 (No. 37014), from the same formation and locality, only 30 cm. 

 in length, evidently represents a young individual of the same 

 species. The cranium and vertebral column are in undisturbed 

 series, with the two dorsal fin-spines in their natural position on 



