260 
substance. This discrepancy between such examples as figs. 18a and 21 can be accounted 
for simply by decortication, because, on several specimens, traces of much shelly matter 
remain, which, if wholly preserved, would bring the shell up to the thictness required to 
make it correspond with fig. 21 or fig. 23. . . 
The dorsal valve is invariably flat, or, at any rate, what little concavity there is, is 
simply a median depression. The surface is composed of scaly concentric lamina?, with 
wavy cross-lines and an occasional small spine. In specimens with the valves in apposi- 
tion the relatively narrow and long area, as compared with that of the succeeding spiecies, 
becomes very apparent. _ 
In the Memoir on the Bowen River Coal Field fossils, three species of Australian 
Strophalosice were described, the present one, the succeeding species, S. Oerardi, and o. 
JuTcesU. At that time much doubt existed as to the limitation of these species, but now, 
I believe, 1 am in a position to satisfactorily 2 )laco all three on a firmer footing. T e 
distinguishing features of S. Glarkei have already been pointed out ; its relation to S. 
Gemrdi will be shown under that species, but a few remarks on S. Juhesii may be made 
The chief point relied on formerly for the separation of 8. Glarkei from S. 
Jukesii, was the deltoid or sub-quadrate form of the latter, as compared with the broa 
oval outline of the former. It appears to me now that the internal characters of the 
dorsal valve afford a far better ground for separation. In S. Glarkei the septum 
extends almost the whole width of the dorsal valve, hut in S. Jukesii it hardly does 
more than reach the middle of the valve. The deeply excavated cordate depressions 
on each side the septum of the former is absent in the latter. In the first-named 
species the renal impressions form together a broad oval curve, and terminate forwar d 
in a line with the front end of the septum; in the second species, on the other hand, the 
renal scars are much more aurate, comparatively broader, but not so oval, and pro]ec 
towards the front far beyond the termination of the septum. These characters, when 
viewed together, present a very different appearance in the two species. 
The original specimens on which I described 8. Juleesii were said to have come 
both from New South Wales and Tasmania, but I believe this will prove a far more 
representative species of the latter than the former country. 
Loo. and Horizon. Pelican Creek, Bowen River, five miles north of Sonoma 
Station ; the same, opposite Palmer’s Old Station; the same, three-quarters of a mile 
above Sonoma Road-crossing; Parrot Creek, Bowen River, four and a-half miles, eig 
miles, and nine miles up ; Cockatoo Creek, Bowen River, balf-a-mile above junction wi ^ 
Parrot Creek ; Bowen River, two miles above Beasley’s Old Public House {B. L. Jkc*; , 
Springsuro (The late James 8mith) —Middle or Marine Series of the Bowen River Co 
J'ield. 
Stiiophalosta Gepardi, Jx - ing . 
PI. 13, fig. 18 ; PI. 14, fig. 18 ; PI. 40, figs. 7 and 8. 
Strophalosia Qerardi, King, Ann. and Mag. Nat. Hist., 1S46, xviii., p. 93. 
Tie Koninek, .VInn. Produotus et Olionetes, 1847, p. 137. 
' ,, King, Mon. Permian Po^is. England, 1850, p. 90, t. 10, f. 6 and 7. 
” Davidson, Mon. Brit. Foas. Braoh., introd.iction, 18,57, t. S, f. 211. 
” ” pyheridgp fil., Prno. R. Pbys. Sno. Edinb , 1880, v., p. 294, t. 12, f. 34-37, t. 13, 
Etheridge Bh, Joiu-n. K. Soc. N. S. Wales for 1883 [1884], xvii., p. 87. 
8p. Ghar. Shell of medium size, ovate-rotund, at times becoming almost 
strongly concavo-convex. Ventral valve convex, most so about the umbonal and 
regions; umbo prominent, rounded, and overhanging the area to some 
short, high, and triangular ; dorsal valve varying from concave to semi-concave, to 
closely the contour of the ventral, assuming a more or less deltoid form, usual y 
