1898.] DR. BASHFORD DEAN ON PAL^OSPOlSrDXLUS GUNNI. 345 



Finally, that the regular grain o£ the stone has produced the ques- 

 tionable markings, as Dr. Traquair maintains, has been pronounced 

 untenable by those petrologists to whom I have shown specimens. 

 The parallel striature he refers to, so common in many matrices, is 

 liner, smoother, more regular, continuous, much fainter, not to be 

 confused with the blunt-ended markings noted in the foregoing 

 specimens. In view of the evidence of additional fossils one must, 

 I believe, regard the markings as representing structures — whatever 

 be accepted as their ultimate homology. Dr. Traquair denied 

 before the British Association (1896) that my fossil had any value, 

 prior to his examination of it, on the ground that in his many 

 specimens there were no traces of the markings. This objection 

 is now obviously invalid, since in his own collection have been 

 found traces of them. Indeed there is reason why among several 

 hundred fossils there might not appear prominent remains of 

 structures as frail as the questionable fin-supports ; for the 

 specimens of Palceospondylus are, as a rule, poorly preserved. So 

 far as I know, in all the materials extant there are very few 

 specimens — a dozen or thereabouts — which deserve to be pro- 

 nounced really good. 



(II.) Dr. Traquair's criticism of my terminology is included 

 under the following beads : — («) the use of the term " oral " for 

 what he believes to be " nasal" ; (6) reference to the " diphycercal 

 (or perhaps heterocercal) " caudal fln ; and (c) supposed confusion 

 of terms " radial " and " basal " tin-supports. 



(«) The first of these is the important one. That the anterior 

 " median cirrated opening " of Palceospondylus was described by 

 Dr. Traquair as entirely nasal, altogether unconnected with the 

 mouth, I have certainly been loth to believe. He refers to part 

 of it in his second paper ^ as " the upper margin of a suctorial 

 mouth," and later as " presumably nasal," ^ and I have referred to it, 

 partly on this account, as equivalent to the mouth-region of a myxi- 

 noid ^ He nowhere states that it is independent from the mouth, 

 and, although his comparison is with Marsipobranchs in general, 

 he repeatedly refers to Myxine ", in which the barbel-bearing ring 

 of fibro-cartilage encircles the openings of both mouth and nose. 

 That the "cirrated" ring should be regarded as nasal only seemed 

 most unintelligible, for it was not probable that Dr. Traquair would 

 ■wish to ally PalcBospondylus to the Marsipobranchs by a character 



' Proc. Eoy. Phys. Soc. Ediub. 1892-93, xii. p. 90. 



2 L. c. p. 318, and Ann. Scot. Nat. Hist. 1894, April, p. 98. 



' He twice refers to the greater length of the lateral "barbels" and their 

 origin " inside the margin of the ring, instead of from its rim like the others " 

 {I. c. p. 96), a condition which further suggests to the reader the division of 

 the opening into ventral (mouth) and dorsal (nasal) halves. 



* E.g. (Proc. Eoy. Phys. Soc. Edinb. xii. p. 319) "... in the recent Marsi- 

 pobranchs, two kinds of cartilage enter into the formation of the cranio-facial 

 apparatus, of which one is considerably harder and more solid than the other. 

 In Myxine the hard cartilage prevails in the cranium, while the soft variety 

 enters largely into the structure of the hyo-lingual parts. A similar condition 

 may have existed in Palmospondylus...." 



Proc. Zool. Soc— 1898, No. XXIII. 23 



