1897.] DB. B. U. TRAQtTAIR ON PALiEOSPONDYLtTS GUNNI. 315 



had been sent to bim by Mr. W. T. Kinnear, of Forss near Thurso. 

 His interpretation of this specimen, along with a magnified figure, 

 will be found in a paper entitled " Is Palceospondylus a Oyclostome ?" 

 published in the ' Transactions of the New York Academy of 

 Sciences' for 1896 (vol. xv.). 



Here (pp. 101, 102) Dr. Dean states that in this specimen "a 

 dusky band may, on either side, be traced taiivvard from the region 

 of the ' auditory capsules.' These bands when examined with a 

 glass are found to resolve themselves into a series of ray-like 

 structures arranged trausversely to the axis of the body, but slightly 



inclined backward They cannot be said to definitely 



take their origin from post-occipital plates, although they certainly 

 appear to, and there is a suggestion that the right occipital plate 

 has been formed of metameral elements. The band of ray-like 

 structures continues, however, caudad of the pectoral region, 

 traceable backwards to the regiou of about one-half the length of 



the vertebral axis Negative as well as positive evidence, 



accordingly, indicates that these fin-like rays were concerned with 

 the presence of paired fins. If this be true, is Palceospondi/lus to 

 be regarded as a Marsipobranch ? " The paper finishes with an 

 arrangement in tabular form of the evidence for and against the 

 marsipobranch affinities of Pakmspondylus, from which it would 

 appear that he still looks upon the cir rated opening as a " mouth," 

 and that he thought the post-occipital plates may " well represent 

 basalia of pectoral fins." After all, the only conclusion to which 

 the author comes is that "the position of the fossil, if not to be 

 regarded as marsipobranchian, is certainly undefiuable." 



As Dr. Dean has been so extremely kind as to send his specimen 

 over to this country that we may examine it for ourselves, I am 

 enabled by this act of courtesy on his part to oifer a few words as 

 to my interpretation of the appearances presented by it. 



It belongs to the class of specimens which may be designated as 

 moderately good. The black substance of the skull and vertebrae 

 is fairly well preserved, but the surface is goue. The post-occipital 

 plates are not well preserved, so that the " suggestion " as to one 

 of them being formed of " metameral elements " is absolutely 

 without value. The vertebral centra are in pretty good condition, 

 some of them in front being so turned up as to show their ring-like 

 conformation with great distinctness. These are the parts seen on 

 the specimen ; if there were anything more we should expect it to 

 be preserved in the same way. 



On examining the specimen with a low power, taking care to 

 turn the head towards the Uyht, we see the dusky band clearly 

 enough on the right ' side, though it is scarcely perceptible on the 

 opposite one ; and we also see the appearance of this band being 

 divided into transversely directed ray-like bodies. Then if we 

 turn round the fossil so that the light may strike on the vertebi-al 

 column from the convex side, then the dusky band with its ray-like 

 markings at once disappears — but not so the black substance of 

 1 In reality the left side, as the specimen, as usual, lies on its back. 



21* 



