ANNIVERSARY ADDRESS OF THE PRESIDENT. lxXXV 



Salweyi, C. Marchisoni, 0. ornatus, restoring therefore to the genus 

 a stability equal to that it had formerly obtained, — and one new 

 genus and species, Auchenaspis Salteri, founded on a specimen perfect 

 in every respect, and yet in size not larger than a fourpenny-piece — 

 a genus closely allied to Cephalaspis, but yet structurally distin- 

 guished from it. 



It is curious and worthy of notice, that the ichthyological portion 

 of this subject has also engaged the attention of Professor Huxley, 

 who has already attained a high place in the ranks of our Palaeon- 

 tologists. Reviewing the question of the affinities of Cephalaspis 

 and Pteraspis, in a paper read before our Society, he refers to the 

 opinion expressed by Kner, that C. Lloydii and C. Lewisii should be 

 separated from the other species belonging to that genus, and placed 

 in a new genus, Pteraspis, which, however, he considered a genus of 

 Cephalopods, and not of Fishes. Roemer again more recently ex- 

 pressed an opinion that the Pteraspides are Crustacea ; but, after a 

 careful microscopical examination of the shields of Cephalaspis and 

 Pteraspis, Professor Huxley has fully established the ichthyic charac- 

 ter of Pteraspis, whilst at the same time he proves its just claim to 

 be considered a distinct genus ; so that this paper was a valuable 

 confirmation of that of Sir Philip Egerton. 



The importance of this inquiry of Professor Huxley had been stated 

 by anticipation, and with his characteristic modesty, by Sir Philip 

 Egerton, who observed, towards the close of his remarks, " much 

 remains to be done with reference to the structural anatomy and true 

 affinities of this curious family — subjects far beyond my grasp, but 

 which I trust ere long will be grappled with by Professor Huxley, 

 who has already bestowed some time upon them, and than whom 

 no one is better qualified for bringing the inquiry to a successful 

 issue." 



Associated with the specimens described by Sir Philip Egerton, 

 were portions of jaws resembling Plectrodus mirabilis rather than 

 P. pleiopristis, an Ichthyodorulite resembling Onchus Murcliisoni, 

 and another, hitherto undescribed, which diifers from the genus On- 

 chus as now restricted, and in some characters approximates to the 

 spines of Ctenacanihus and Erismacanthus ; Sir Philip, however, offers 

 a proper caution as to a reliance upon the forms of spines in deter- 

 mining specific differences. Sir Roderick Murchison added a few 

 useful remarks on the relative position of the Ludlow strata which 

 had supplied the fossils described by Sir Philip Egerton, as a note to 

 his paper. In the section of the railway- cutting- north of Ludlow, 

 some of the highest beds of the Ludlow Pock have been brought, by 

 an up-cast, immediately in contact with the Old Eed Sandstone, consti- 

 tuting a small insulated mass, which is younger than and distinct from 

 the bone-bed of the Upper Ludlow Rock, described in the ' Silurian 

 System ;' for, whilst the bone-bed is overlaid by the Downton-Castle 

 building- stone and other grey strata which constitute the loAver por- 

 tion of the tilestones, the Railway-band, about 6 feet thick, is con- 

 formably surmounted on the south-east by micaceous sandstone and 

 red shale or marl. Though, however, higher in the series, this thin 



vol. xrv. g 



