234 
REPORT ON JURASSIC AND CARBONIFEROUS FISH- 
REMAINS. 
By Frederick Chapman , A.L.S., &c., Palaeontologist to the National 
Museum. 
Jurassic Sandstone with Ceratodus. —Parish of Kirrak, S. Gipps- 
land. Plate XXXIX. 
The specimens numbered 4,413 are two opposite halves of a bore-core 1 2 
in fine-grained, greenish, carbonaceous sandstone. Each of the apposed 
surfaces bears a portion of the split outer lamina of a scale referable to 
the genus Ceratodus. Although the scale is large, it is not inconsistent 
with the idea that it may belong ito the same species of fish, Ceratodus 
avus, to which the tooth from similar beds at Cape Paterson was referred 
by Dr. A. S. Woodward 3 . The allied living form, Neoceratodus forsteri , 
also has very large body scales, 11 often measuring more than 4 inches 
across ” 3 . It is of some importance to note that the above fossil came 
from the same district as the tooth described by Dr. Woodward. 
The discovery of this specimen is of great interest and scientific value, 
since, so far as I am aware, no scales of a fossil Ceratodus or Neoceratodus 
have hitherto been recorded; the various occurrences from the Biinter Series 
onwards, being based on the teeth, a skull, and a tail. 
Description. —Scale of Ceratodus (?) avus, A. S. Woodward. Colour, 
a dark purplish-brown. Surface dull, with a slight sheen in places. 
Sub-rhomboidal; the embedded area somewhat rounded, the exposed por¬ 
tion obtusely pointed. The marginal border of the exposed part of the 
scale is occupied by a series of slightly undulating, parallel and depressed 
ridges, which feebly persist also in the basal area, and indicate lines of 
growth. Surface of basal area divided into rhombs or trapezes by a net¬ 
work of tissues in the outer layer of the scale. The shape of this scale 
indicates that it came from the ventral surface of the body, probably near 
the pectoral region. Although the squamation of Ceratodus is generally 
referred to as of the cycloid type, it was shown by Prof. Williamson 
and Dr. Giinther that the scales of Ceratodus have a peculiarly interesting 
structure. 4 They consist of two strata, an inner and thicker, composed of 
numerous layers (Giinther counted about 42) of fibrous cartilage—which has 
since disappeared in the fossil—and an outer layer, comparatively thin, of 
phosphatic and calcareous material, in which numerous calcareous granules 
are embedded in the attached portion of the scale, and which appear in 
places on the surface as blunt spines surrounded in some cases with a 
series of foramina. 4 In this, therefore, Ceradotus seems to show an 
annectant character, linking it with the ganoid or enamelled scale type, 
and in our fossil similar characters are to some extent present. Upon a close 
examination of the base of the scale in the present example there is seen 
distributed over the surface of the areolae a granular deposit of a pale bluish 
tint, such as is found in the layers on a tvpical ganoid scale. The granu¬ 
lations occur towards the base of the scale, often arranged in fine lines in 
a fore and aft direction, but sometimes radiating, the granules thus im¬ 
parting a micro-shagreen character to that part of the scale-surface. 
1. Other data on label as follows : —“No. of Drill, 9’ ; No. of Bore, 2 ; No. of Sample, 27 ; Depth, 26 feet. 
Date, 13th October, 1908.” 
2. Annals and Mag-. Nat. Hist., ser. 7, vol. XVIII., 1906, pp. 1-3, pi. I. Reprinted in Records Geol. 
Survey Viet , vol. II., pt. 2,1907, pp. 135-137. 
3. Stead, D., “ Fishes of Australia,” 1906, p. 230. 
4. Gunther, A. Phil. Trans. Roy. Soc., Vol. CLXI., 1872, p. 516, PI. XXXI. 
