336 PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. [April 24, 



Spiripera allied to S. striata, Sow. PI. XVIII. fig. 8. 



So variable a form as the above may have referred to it any species 

 with equally convex valves, a moderately elevated mesial fold, a 

 variable number of radiating ribs, and a straight hinge-line. We fail 

 to recogTiize the reticulated ornamentation of the outer surface, 

 arising from the want of the perfect outer shell. 



We possess only the dorsal valve of this form, and, therefore, are 

 not justified in giving it a varietal name. I figure it amongst other 

 shells &c. occurring in the Don-Eiver Carboniferous rocks. It is 

 said to be abundant in Queensland ; I, however, only recognize one 

 valve amongst the Daintree collection. Many varieties of S. bisul- 

 cata, Sow., especially some forms of the var. semicircularis, Phill., 

 also very much resemble our shell. I name these affinities in the 

 hope that attention may be paid to them when better specimens 

 occur ; and the works of Davidson, De Koninck, M'Coy, &c. are now, 

 or should be, in the chief Colonial libraries. 



Loc. Don River, N. Queensland. Form. Carboniferous. 



Choitetes cracowensis. Ether. PI. XYIII, fig. 2. 



The subgenus Clionetes seems only to be illustrated by one species ; 

 but of this there are many individuals. 



Sp. char. Shell transversely oblong or semicircular, wider than 

 long, both valves ornamented with many ribs ; hinge-line straight, 

 not so long as the width of the shell, area narrow and parallel — 

 ventral margin convex. Cardinal angles rounded and fiattened at 

 their extremities. Ventral valve slightly convex. Dorsal valve 

 nearly flat, or following the curve of the ventral. Beak small, ap- 

 parently slightly incurved, but not covering the hinge-line. The 

 place of the hinge-spines faintly traceable. The surface of the shell 

 covered by what must have been short and stout spines numerously 

 distributed. 



Ohs. The species of this genus vary to an immense extent, so much 

 so that they may be almost recognized according to their locality — 

 habitat and bathymetrical conditions, &c., being evidently the cause. 

 This shell resembles G. hardrensis, so abundant in the Devonian and 

 Carboniferous rocks of Europe, but differs from the allied British 

 species, C. BucMana and C. Dalmaniana. With the latter it has no 

 affinity, the ribs being much finer than in either of them, the spines 

 being more numerous and the hinge-line longer ; with the variable 

 C. hardrensis, however, it has considerable affinity, especially with 

 Phillips's type form ; but the spines are much more numerotis, and 

 the cardinal angles more pronounced and flattened. Whether the 

 ribs bifurcated or not I cannot determine. 



The abundance of this shell at Cracow Creek, and its differences 

 from other known species, suggest the name I have ventured to give it. 



Log. Cracow Creek. Form. Carboniferous. 



PlETJEOTOMARIA ROTUNDA, Ether. PI. XVIII. fig. 3. 



Shell turbinate or trochiform, with four whorls ; apex slightly de- 



