Palichthyologic Notes. No. 5.—On two new species of Placoid Fishes from the Coal Measures

Abstract

Some years have now elapsed since I first became aware of the occurrence of a large species of Cestraciont in the shale-beds of the Lanarkshire coal-field; but I have postponed from time to time the task of describing it, partly from an unwillingness to rush before the public, on the discovery of each new species, with inconsiderate haste in the general scramble for priority of credit, now, I regret to say, so much the vogue, but principally in the hopes that some cognate materials might come to light to render the communication more worthy of the time and attention of the Society. The recent discovery of a second species, and the increased and increasing interest which the researches of the last few years have imparted to the fauna of the Carboniferous epoch, may perhaps now be considered a sufficient justification for the present memoir, meagre tough it be. The first specimen which attracted my attention to this subject was a defence-bone discovered by a collector named Doran in the black shales of the Carluke district. This is now in the British Museum. Similar rays have since been found in several localities. The Museum of Practical Geology possesses specimens from the Talwyn works, near Mold in North Wales, in shale; and from Hady, near Chesterfield, in ironstone. And Lord Enniskiilen and myself have several very perfect examples from the neighbourhood of Dalkeith, where they are associated with finer specimens of Gyracanthus spines than I have seen from any other locality. Ctenacanthus