DESCRIPTION OF THE FOSSIL REMAINS. 53 



head from those of the carapace. . . . The excessive development, in 

 short," he concludes, "of the central plate of the carapace, which reaches the 

 articulation of the head, the absence of a thoracic cincture making the round 

 of the body, and the distinct separation of the occipital articulation, will 

 always distinguish this genus from that of pterichthys." 



This is decisive language, nor is anything more of descriptive detail re- 

 quired to make the structure and the generic characters of pamphractus 

 thoroughly understood. But as matter of geological history, as well as of 

 controversy, it may be proper to state, that when the accuracy of these dis- 

 tinctions was challenged by Dr. Fleming and Hugh Miller, upon the ground 

 of alleged exaggerations in my plate-figures, Agassiz at once repelled the 

 assertion. The impressions on the fossil slab forwarded to Neufchatel are 

 ELEVEN in number, three of the "broad" and eight of the " narrow " species; 

 and comparing the one with the other, the print with the fossils, he records, 

 " They have been figured very fairly by Dr. Anderson, in his interesting 

 Memoir on the Geology of Fifeshire." The print, in fact, is a perfect tran- 

 script of the fossil, as if taken in a mould, curves, projections, plates, arms, 

 and tubercles all duly and " fairly " preserved as in the original ; and with 

 all the materials, and so many actual forms of the creature before him, 

 Agassiz hesitated not to change his views, and to feel assured that it was 

 really a pamphractus, and not a pterichthys that he was examining, and de- 

 cided for the new genus accordingly.* 



Sir Philip Egerton, however, and I believe many other eminent authorities, 

 dissent from the views of M. Agassiz on the revised and altered cognomen of 

 the Dura Den fossil. In a conjunct paper read before the Geological Society 

 of London on the 19th April 1848, and published thereafter in the Transac- 

 tions of the year, there occurs the following statement : — " In searching for 

 further evidence in support of my views, by comparing pterichthys with the 

 description and figures given by Agassiz of the allied genera, I have been 

 surprised by the great similarity between the restoration of the genus Pam- 

 phractus and the dorsal integuments of Pterichthys. Having never seen a 

 specimen of Pamphractus, I should not be justified in expressing any positive 

 opinion regarding this genus, but I cannot help thinking that it is founded 

 on a specimen showing the true dorsal arrangement of the lorication of Pter- 

 ichthys. . . . The most important point for my argument is fortunately 

 that which is best known, namely, the occurrence of a central lozenge-shaped 



* Dr. Anderson, dans une notice tres-int^ressante qu'il a publice sur la Geolot/ie et la 

 Botanique du comte de Fife, donne la figure d'un poisson (Fig. 6 de sa planche) qtii res- 

 semble beancoup a mon Pamphractus hydrophibis, mais qui en differe cependant par la forme 

 plus allongee de la tete et par le developpement de la ceinture thoracique qui est visible 

 entre la tete et la carapace. A moins que ces differences ne soient I'expression dea carac- 

 teres particuliers des faces superieure et inferieure de la carapace, que je n'ai pas pu com- 

 parer entre elles, il faudra considerer ce fossile comme une espece particuliere que je signale 

 a I'attention des geologues ecossais, en proposant de I'appeler Pamjjhractus Andersoni. Je 

 suis d'autant plus dispose a considerer lo poisson de Di'. Anderson comme une espece a part, 

 que la forme de ses contours difiere de celle du PamjjJiractus hydrojjMlus ; mais une com- 

 paraison d'un nombre plus considerable d'exemplaires mieux conserves pourra scule decider 

 cette question. — Monograi)Me, Chap. iii. 



