8 Prof. Hughes—Lower Cambrian, Bethesda, N. Wales. 
paucidens, Ag: sp. These are the scales (figs. 26 and 27), the 
mandibles (figs. 82, 33, and 386), the sections of teeth (figs. 84 and 
35) ; the bone d (fig. 46), which I look upon as the lower end of 
the clavicle; and the interspinous piece (fig. 48), which Hugh 
Miller figured as the “ischium of Asterolepis.” The latter is indeed 
a very curious bone, and it is not at all remarkable that the author 
of the “ Footprints” should have sought to identify it with the 
basal bone of a ventral fin constructed in teleostean fashion. 
Knowing that such a pelvic fin-element could hardly have existed 
in either Homosteus or Glyptolepis, the bone was long a puzzle to 
me, until one day I observed a very similar bone supporting the 
distal set of interspinous bones of the second dorsal fin in a 
specimen of Glyptolepis leptopterus, also in the Hugh Miller Col- 
lection. A similar bone supporting three smaller interspinous 
elements was described and figured by Sir Philip Egerton in Trists- 
chopterus.} 
As regards the species of Homosteus, which has been under con- 
sideration, no specific name was given to it by Hugh Miller. By 
Morris? it was catalogued as the ‘‘ Asterolepis Asmusii” of Agassiz, 
but I know not on what ground. Certainly I can find no resem- 
blance between the sculpture of the surface of the plates of A. 
Asmusit, as given in Agassiz’s figures, and that which characterizes 
the present fish in which the tubercles are small, sharply defined, 
with prominently stellate bases, and for the most part closely placed. 
Nor can it be identified with the species of Homosteus described by 
Asmuss from Dorpat, and so I would propose that for the future 
it be known as Homosteus Milleri. 
EXPLANATION OF PLATE I. 
(In all the figures the same letters refer to the same things.) 
m. 0. median occipital. e. o. external occipital. mm. marginal. c¢. central. pf. o. 
post-orbital. y. o. pre-orbital. pé. e. posterior ethmoidal. a. ¢. anterior 
ethmoidal. y. maz. premaxillary. m. nasal opening. m. d. median dorsal. 
a. d. 1, anterior dorso-lateral. yp. d. J. posterior dorso-lateral. a. /. anterior 
lateral. yp. 7. posterior lateral. 7. 7. interlateral. «@. v. /. anterior ventro- 
lateral. yp. v. 2. posterior ventro-lateral. mm. v. posterior median ventral. 
A, B, C, three facial plates lying below the margin, anteriorly of the cranial 
shield of Homosteus. 
Fie. 1. Sketch of a specimen of Homosteus Miller’, Traq., in the John Miller Col- 
lection, Museum of Science and Art, Edinburgh. 
Fre. 2. Restoration of the top of the head in Coccosteus decipiens, Ag. The dotted 
lines indicate the distribution of the grooves of the lateral-line system. 
Fic. 3, Sketch of a specimen of Coccostews minor, H. Miller, from Thurso, the 
vertebral column omitted. Hugh Miller Collection. 
IJ.—Nore on tut Lower CamBriaANn OF Betusespa, Norta WALES. 
By Prefessor T. McKrnny Hucues, M.A., F.G.S. 
NTIL quite lately no fossils had been found in the Lower 
Cambrian of Bethesda. Indeed we had almost given up the 
hope of obtaining any evidence of the life of the period represented 
by them, because of the great alteration in the character of the rock 
resulting from the severe mechanical action to which it had been 
_ 1 Dee. Geol. Survey, vol. x. p, 52, plate 5. | * Catalogue British Fossils, p. 318.; 
5°On Plate I. in Fig. 2, for p.e. read pt.e. In Fig. 3, for e.m. read e.0. 
