Pisces. | UPPER PALAZOZOIC VERTEBRATA. 607 
The upper and lower margins of the scales are said by M. Agassiz and Sir P. Egerton to be arched, but they 
are not in the slightest degree more so than in the German copper-slate species. 
Position and Locality—Extremely abundant in the Permian marl-slate of East Thickley. 
PALAONISCUS GLAPHYRUS (Ag.) 
Ref—Ag. Poiss. Foss. Vol. II. t. 10 c. f. 1, 2. 
Desc.—General form, deep-ovate, increasing from the head to the origin of dorsal fin, and abruptly 
attenuated behind the anal fin to form the pedicle of the tail, which is there only half the depth of the body in 
front of the dorsal; head very small, little more than one-sixth the entire length; mouth small; orbits very 
large; from the origin of the pectoral to origin of yentral fins rather more than from the origin of ventral to the 
origin of anal fin, from the origin of which to the origin of the caudal is considerably less than the space 
between the origin of the ventral and anal fins, but exactly equals the depth of the body at the latter point; 
greatest depth of body (at middle of length) equal to one third of the length, from the edge of the operculum 
to the extremity of lower lobe of caudal fin; scales very large, oblong, about one-third longer than wide on the 
flanks, where near the head three occupy a space in depth of little more than three lines, and four occupy the 
same space in length; the depth of the body equalling about three and half times a space equal to a depth of 
three scales, on all the anterior parts of the body. Surface of the scales smooth and polished, posterior edge 
coarsely serrated with about eight denticles. Average length little more than three inches, depth of body 
ten lines. : 
This little species is very easily distinguished, by its broad thick form, abruptly attenuated towards the tail, 
and its very small obtusely angular head, but most particularly by the great proportional size and the coarse 
notching of the posterior edges; this latter character is more strongly marked than in M. Agassiz’ figure, 
there being in our specimens fewer denticles to the length of a scale: the scales are very thin and brittle, with 
the usual strong articulating process projecting internally from their upper edge, and forming the usual 
internal ridge along the middle. In all the specimens yet known the caudal fin is imperfect, so that the 
precise form of the upper lobe is not known, The bones of the head are marked with few, obtuse, diverging 
sulci. 
Position and Locality —Rare in the Permian marl-slate of Ferry Hill. 
PALZONISCUS MACROPHTHALMUS (Ag.) 
Ref—Ag. Poiss. Foss. Vol. II. t. 10¢, f. 3; King Perm. Foss. t. 22. f. 2. 
Desc.—Elongate, slender, body of nearly uniform depth from the head to origin of anal fin, from whence 
it tapers rapidly to the origin of the caudal; head very large, obtuse, slightly exceeding the body in depth 
and width, its length from the nape to the tip of snout is comprised four and half times in the total length ; 
from the latter point to the extremity of tail, measured from snout to origin of pectorals, the head is com- 
prised about three and half times in the total length; depth and width of head slightly greater than that of 
the body ; lower jaw short, slender; orbits large, their anterior margin nearly over the anterior end of the 
lower jaw; from nape to origin of dorsal fin the same length as from the latter point to the origin of the 
caudal, so that the whole of the dorsal is nearer to the tail than to the head, and is vertically over the interval 
between the ventral and anal fins ; pectorals rather small, elliptical ; from origin of pectorals to origin of ventral 
fins slightly more than from the latter point to origin of anal, the distance between the origin of the two latter 
fins being equal to the depth of the body at the same point; caudal moderately forked; all the fin-rays ex- 
tremely slender. Scales very small, nearly oblong, and uniform over the whole body, slightly deeper than long 
in the anterior half, nearly equilateral in the posterior half, diminishing in size, very acutely rhombic, and much 
longer than deep on the upper lobe of the tail; about the middle of the body six scales in length and four 
in depth occupy a space of two lines, the space including such number being comprised three and half times in 
the depth of the body at same place. Surface marked with very deep, coarse, short, interrupted grooyes, very 
[FASC. I11.] 4] 
