153 
Carboniferous Limestone comes to light, and also in Asia, America, the 
Ural, and Australia. It seems to be rather rare in Australia, as Mr. W. B. 
Clarke has found only one specimen of it on the banks of the Williams, 
associated with Spirifera dupUcioosta, Phillips. 
Productus brachyth.®:rus, G. Soioerhij} 
PI. X, Pig. 4, and PI. IX, Pig. Ir 
Jdroductus brachij Ihcerus, G. Sowerby, 1844, In Darwin’s Geol. Obs. Vole. Islands, p. 158. 
,, ,, J. Morris, 1845, In Strzeleclii’s Phys. Descr. N. S. Wales and 
V. D. Land, p. 284, pi. 14, fig. 4c (fig. 4a and 45 exclusis). 
,, ,, P. McCoy, 1847, Ann. Mag. Nat. Hist., XX, p. 235. 
,, imdulatus, Idem, 1847, iUd., p. 23G, pi. 13, fig. 2. 
,, hrac1iyth(erus, L. G. do Koniuck, 1847, Eech. Anim. Poss., I, p. 102, pi. 16, 
fig. La, 15 (fig. Ic and Id exclusis). 
,, ,, J. Dana, 1849, Geol. Wilkes’ IT. S. Explor. Exped., p. 686, pi. 2, 
fig. 8. 
This shell is of moderate size, inflated, slightly transverse, and sub- 
trapezoidal in contour. The ventral valve is gibbous, with abrupt sides, slightly 
depressed in its median portion, but having no well-marked ventral furrow. 
Its outer surface is ornamented with a great number of very small longi- 
tudinal ribs, giving rise to acicular tul)es seldom well preserved ; these tubes, 
having their origin at some distance from the point where they cross the 
shell in order to leave it, produce on the surface small elongated tubercles, 
the anterior extremities of which are pierced when the tul3es have disaj)- 
peared. The ears are short, rather wide, and supplied with a row of five or 
six nearly vertical tubular spines, with rounded bases, parallel to the hinge 
line. The beak is tumid, short, scarcely 2 )rojecting over the hinge line, which 
is straight, and shorter than the transverse diameter of the valve. Near the 
beak there are generally some faint traces of concentric wrinkles. I have 
liad an opportunity of observing the interior structure of this valve on several 
well-preserved moulds, and it is quite different from that which Mr. J. Morris 
has attributed to it from a mould which he believes to have been produced 
by it, but which really belongs to another species, as I suspected as long ago 
' [Vide R. Etheridge, Junr., Geol. and Pal. Q’land, 1892, p. 248ci seq., t. 12, f. 10-13, t. 13, f. 5 (?), t. 44, 
f. 14.— w.s.n.] 
2 [PI. 11, fig. 1.— w.s.n.] 
/ 
