141 
Froductus riparius, H. Trautschold, 1867, Bull. Soc. Imp. Nat. Moscou, III, p. 35, pi. 5, fig. 2. 
,, Cora, J. "W. Dawson, 1868, Acad. GeoL, p. 297, fig. 98. 
,, „ Shumard, 1854, in Marcy’s Explor. Eed Eiver of Louisiana, p. 189. 
,, cfr. Corel, Er. Toula, 1869, Sitzung. K. Akad. Wissen. Wien, LIX, p. 441. 
„ „ E. Etheridge, 1872, Quart. Journ. Geol. Soc., XXVIII, p. 328, pi. 15, 
fig. 1 and 2. 
,, „ L. G. de Koninck, 1873, Eech. Anim. Eoss., Terr. Carb. Belg., II, p. 20, 
pi. 1, fig. 15.' 
,, ,, D. A. Derby, 1874, Bull. Cornell Univ., I, No. 2, p. 49, pl.*2, fig. 17, 
and pi. 6, fig. 17. 
,, „ Er. Toula, 1875, Sitzung. K. Akad. Wissen. Wien, LXXI, p. 549. 
,, ,, H. Trautschold, 1876, Kalkbruche von Miatchkowa, p. 53, pi. 5, fig. 1. 
This species has been so well described and so perfectly figured by a 
number of Paleontologists that I need not enter into details regarding its 
distinguisbing characteristics. I will merely state that the Australian 
specimens under my notice belong to a variety usually distinguished by its 
great size, as may be readily seen in the figure given by me. The small 
longitudinal ribs, with which the surface of this variety is covered, are 
generally a trifle thicker and less regular than in the other varieties. In 
every way these specimens resemble those which I have collected in abundance 
from the Carboniferous Limestone of Vise, and which I have described and 
figured in my works. 
Dimensions . — One specimen found by Mr. W. B. Clarke is about ten 
centimetres long by about seven broad. 
Horizon and Localities . — As I have elsewhere stated this species is 
remarkable for its wide geographical distribution ; it appears nearly everywhere 
where there are Carboniferous beds, in Asia, America, Europe, and Australia. 
It apparently existed before the formation of the first beds of the Carboniferous 
Limestone, and it continued up to the epoch which saw the deposition of the 
last beds of the same limestone. It is noteworthy that it reaches its greatest 
size just when it is on the point of vanishing from among the then living 
fauna. The Rev. W. B. Clarke found several examples of this Froductus in 
a compact brownish-yellow limestone near Tilleghary. Mr. B. Etheridge 
* A complete synonomy of this species will be found here. 
