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Show 314 DR. R. H. TRAQUAIR ON PALcEOSPONDYLUS GUNNI. [Mar. 16, thought to represent fin-rays, were not organic and had nothing whatever to do with the fish. Similar ridges were to be seen on a specimen with Palceospondylus in the Museum of Practical Geology, but had no relation to the fossil. The following papers were read :- 1. Note on the Affinities of Palceospondylus gunni, Traq. In reply to Dr. Bashford Dean, of N e w York. By R. H. T R A Q U A I R , M.D., LL.D., F.R.S.1 [Keceived March 16, 1897.] Those who are acquainted with my papers on Palceospondylus gunnl will remember that my principal reason, in my last contribution to the subject, for assigning a Marsipobranch affinity to this singular little Devonian organism was the presence of a cirrated opening, presumably nasal, situated in the front of the cranium. M y words were :- " What is the nature of this aperture with its strange fringe of cirri ? It cannot be a sucker like that of the larval Lepldosteus. The more obvious comparison-and that which is in harmony with the rest of the structure of our fossil-is that with the single nasal opening of Myxlne or Petromyzon. And if this view be the right one, then Palceospondylus is monorhinal, and is a Marsipobranch."2 I was therefore not a little surprised to find the following statement by Dr. Bashford Dean at p. 70 of his recent work on ' Fishes Living and Fossil,' published after he had received and read the paper from which the above extract is quoted:-" There can be no doubt that Palceospondylus possessed a ring-like mouth surrounded by barbels like those of a Myxinoid, and that it lacked paired fins." Not that Dr. Dean seems to dispute my reference of the cirrated opening to a nasal category-on the contrary he reproduces my restoration of Palceospondylus without raising any question of the kind. So I can only conclude that he did not read my description with that amount of care which would have prevented so serious a misunderstanding of my words, wdiich surely could not have been plainer. In this work, however, the author looks favourably on the idea of the Marsipobranch affinities of Palceospondylus, even to the extent of speaking of it as " the fossd remains of what seems undoubtedly a Lamprey " (p. 65). More recently, however, Dr. Dean has seen reason to change this opinion after examining a specimen of Palceospondylus which 1 Communicated by A. SMITH WOODWARD, Esq., F.Z.S. 3 Proc. Roy. Phys. Soc. Edinb. vol. xii. 1894, p. 314. |