316 DE. E. H. TEAQTTAIE OX PAL.IOSPO'DYLTJS GITJNI. [Mar. Ifi, 



the rest o£ the fossil. Then if we examine the specimen further 

 with a higher power, we should find that these striated markings 

 contain not a particle of organic tissue — they are mere shadoivs-, 

 so that Dr. Dean's expression " a series of ray-like sirudvres'' is 

 surely iuapplicable to them, and the figure or them which he gives 

 in his paper is quite misleading. 



There is no doubt that the outer margin of the " dusky band," 

 lettered "marginal body-wall" in Dr. Dean's figure, represents a 

 slio-htly elevated ridge on the stone, and that the "ray-like 

 stnictiires " are slight furrows brought into relief only when the 

 specimen is so held that the light brings out their shadows. 



The next thing to be observed is that these ray-hke shadows 

 are not limited to a position iiiternal to the line B.W . in Dr. Dean's 

 figure, but extend beyond it towards a second longitudinal line 

 parallel with the first," and there is even an indication of a third 

 one. Furthermore, if we examine the whole surface of the stone, 

 carefully turning it so that the hght may fall on it from various 

 directions, we shall be surprised to find indications of similar 

 striated markings cropping up here and there quite apart from the 



fossil. 



Consequently my belief has come to be, that these markings, 

 considered by Dr. Bashford Dean to be rays of a pectoral fin, are 

 petrological and not palaeontological in their nature— that they are, 

 in fact, inorganic and have nothing to do with the fossil itself, 

 which stands clearly out from them in its deep black contour of 

 calcified cartilage. 



But even if these markings were organic and belonged to the 

 specimen of Palceospondylus with which they are associated, 

 Dr. Dean's interpretation of them is still inconsistent. For if the 

 outer edge of his "dusky baud," marked B.W. in his figure, 

 be really the "marginal body-wall," then his supposed " radial-like 

 supports (of paired fins)," which pass inwards from this line, must, 

 according to his own theory of the paired fins, be " basals " and 

 not "radials." Nevertheless he also says of the post-occipital 

 plates that they " might well represent basalia of pectoral fins."_ 



Apparently still under the conviction that the cirrated ring which 

 I have interpreted as nasal is oral in its nature (how a mouth 

 could o'O directly into the front of the cranium I fail to see), he 

 leaves the nose, upon which I have naturally placed the principal 

 weight, altogether out of consideration in his summary of characters 

 for and against the marsipobrauch afiinities ot Palaospondyh(s. 

 And note his remark : " Moreover it is possible that the ventral 

 ' cirrhi ' are displaced structures from the cranial region, as one of 

 the specimens examined by the present writer seems to indicate." 

 Of course these " ventral cirrhi," namely the cirri on the ventral 

 half of the nasal ring, are cranial structures, and I certainly did 

 not describe them as anything else ! It is really a matter for 

 regret that Dr. Dean did' not, as it would seem, read my paper 

 with a little more care. Although Dr. Dean admits that the 

 caudal fin of Falaospondylus is "essentially marsipobrauchian," 



