157 
part; tlie beak is small, and not prominent. The exterior ornamentation 
consists of a large nnmher of small, elongated, rather thin, tubercles, regularly 
arranged in a quincunx, having probably given rise to tubular spines. 
According to Mr. Etheridge the dorsal valve is nearly flat, its surface shows 
traces of tubercles and spines, and it is also ornamented with concentric rings 
of growth. I have had no opportunity of observing an actual sjoecimen. 
Dimensions. — One rather well-preserved specimen was thirty-one 
millimetres long by thirty-five broad ; another specimen was 4’5 centimetres 
long by five centimetres broad. 
Relations and Differences. — This species is closely allied to P. muri- 
eatus, Phillips ; it differs from it by its much greater size, by the more 
regular arrangement of its tubercles, and by being less elongated. It must 
not be confounded with P, Glarhianus, Derby, which is quite another species. 
Horizon and Localities. — Mr. Daintree found this species on the banks 
of the Bowen PJver, Queensland ; and Mr. W. B. Clarke, to whom it has 
been dedicated, found it in a greyish limestone at Branxton, and in a brownish 
calcareous conglomerate at Burragood, on the Paterson Biver, in New South 
Wales. 
PnoDTJCTUS ACULEATUS, Martin. 
PL XI, Fig. 6. 
Anomites aculeatus, Martin, 1809, Petrif. Derbiensis, p. 1, pi. 39, fig. 9 and 10 (non 
Scbloth). 
Rroductus ,, Sowerby, 1814, Min. Conch., I, p. 156, pi. 68, fig. 4. 
,, ,, L. Gr. de Koninck, 1847, Eech. Anim. Foss., I, p. 144, pi. 16, fig. 6. 
,, ,, M. V. Griinewaldt, 1860, Mem. Acad. Imp. St. Petersbourg, 
II (7), p. 125. 
,, ,, T. Davidson, 1861, Mon. Brit. Carb. Bracb., p. 166, pi. 33, fig. 16-20. 
,, Youngianus, Idem, 1861, ibid., p. 167, pi. 33, fig. 21-23. 
,, aculeatus, L. G. de Koninck, 1872, Eech. Anim. Foss., II, p. 35, pi. 1, fig. 20. 
,, ,, F. Toula, 1875, Sitznng. K. Akad. Wissen. Wien, LXXI, p. 552, 
pi. 2, fig. 10. 
This shell is of medium size, suboval or rounded in contour ; its ears 
are small, and readily fall off ; its shell is thin, nacreous, and iridescent ; its 
hinge line is straight, and never as long as the transverse diameter. The 
