96 
THE GEOLOGIST. 
to strenoftlien that conviction." (I had just written him to that effect.) 
Mr. Walker has, undoubtedl}^ the merit of first making this discovery 
public ; this he did in an admirbale paper, describing most accurately this 
species, H. Fleniingi, and stating his conviction that it belonged to the 
genus Glyptolepis, This paper was read on, I think, the 22nd of Novem- 
ber last, before a meeting of the Literar}^ and Philosophical Society of St. 
Andrew's, and has since been published in the 'Annals and Magazine of 
Natural History.' 
JS^ot only must the Holoptychius Flemingi hereafter be looked on as 
belonging to the genus Glyptolepis, but it seems to me exceedingly pro- 
bable, that Holopt3'chius may ere long be altogether merged into that 
genus. The only species of Holoptychius on which I have never yet been 
able to detect scales, showing the crescent of points on the anterior half so 
characteristic of those of Glyptolepis, is H. Andei^soni, and this I am at 
present inclined to think not a good species at all. Of Holoptychius 
giganteus, the only good specimen I have yet examined is the superb one 
in the collection of Lady Kinnaird ; of this it is the ventral surface which 
is exposed, and on the anterior portion the scales show very distinctly the 
characteristic markings of the Holoptychius giganteus of Agassiz ; along 
the flanks on both sides they as clearly assume the Gl3'ptolepis character, 
in many instances showing the crescent of points so distinctly as to be 
readily observed by the unaided eye, while towards the tail the scales 
assume the exact appearance of those on Holoptychius Andersoni ; indeed, 
so exactly does this fish resemble H. Andersoni in form, in the comparative 
size and disposition of the scales, in the position, structure, and form of 
the fins, so far as preserved, in the comparative size and form of the head 
and jugular plates, indeed in everything except size, that I am much 
inclined to think H. Andersoni the j^oung of H. giganteus, increased age 
developing the different sculpturing on the scales. Mr. Walker refers in 
his paper to a very imperfect specimen of this fish in the St. Andrew's 
Museum, the scales along the flanks also showing the crescent of points 
on the anterior half, the others resembling those of H. giganteus. Mr. 
Walker also pointed out to me what I fully concur with him in thinking a 
species, nearly allied to, but distinct from H. Flemingi, with which it 
seems hitherto to have been confounded, and in this every scale sufficiently 
preserved appears to have the crescent of points as in Glyptolepis. In a 
specimen now in my possession, which was obtained by the late Mr. 
P. Dufi* of Elgin, from the Bishop Mill (Elgin) sandstones, and which has 
been named, I think correctly, oiohilissimus ; I have also been able to 
detect one scale having the crescent of points well preserved, and I am 
informed by Professor Huxley, that the typical specimens of Holopt. 
Sedgwichii, in the Cambridge Museum, present unmistakable Glyptolepis 
scales. 
Mr. Mitchell mentions a Paper communicated by me to the Geological 
Society of London, and published in their Journal for J^sovember last, in 
which I first drew attention to the occurrence of Gh'ptolepis scales in the 
Dura Den Sandstones, and in which I notice a fish as a new species of 
Glyptolepis. This fish, however, I now believe to belong to some other, 
probably new genus, the caudal and other fins, as well as the general form 
too little resembling Glyptolepis, while of the scales it is only the internal 
structure which is shown, and although on one or two the external sculp- 
turing is imperfectly preserved, yet the body where these are situated 
being a good deal twisted, they may have belonged to some of the many 
other fishes scattered over the flag on which this is preserved. 
Thus at present stands the case Holoptychius versus Glyptolepis ; it \%, 
