178 BECORDS or THE AUSTRALIAN MUSEUM. 



LITTLE-KNOWN and UNDESCRIBED PERMO-CAR- 



BONIFEROUS PELEOYPODA in the AUSTRALIAN 



MUSEUM. 



By R. Ethbridgb, Junr., Curator. 

 (Plates xxxi. — xxxiii.) 



Genus Stutchburia,* ye^i. nov. 



In our Pernio-Carboniferous formation are two bivalves that 

 have been variously referred to Orthonota by Morris, Cardinia by 

 Dana, and one of them to Pleurophorus by DeKoninck, the deter- 

 mination of the last named author having been at various times 

 accepted by myself and others ; possibly also one or more of the 

 shells from the same series of rocks, termed Cypricardia by Dana, 

 may be congeneric. I have, however, for some time past, from 

 the edentulous nature of the shells in question, doubted the pro- 

 priety of these references. 



The species are Orthonota % costata, Morris ( = Pleurophorus 

 morrisii, DeKon.), and O.'i compressa, Morris, which may, or 

 may not be only the internal cast of 0. costata. To these may 

 perhaps be added Pleurophorus biplex, DeKon., and P. randsi, 

 mihi. The internal structure of the two first, and particularly 

 of 0. ? costata is known to some extent, but that of the third very 

 little, and of the fourth not all. It is by no means certain that 

 P. biplex, and P. randsi are congeneric with 0? costata and 0? com- 

 pressa, and in consequence are left for the present in Pleurophorus. 

 At the .same time there is still an undescribed form in our Marine 

 Series, that appears to be generically identical with Pleurophorus: 

 this will be described later. 



In form 0. ? costata and 0. '? compressa are narrow, transversely 

 elongate, and more or less compressed Molluscs, inequilateral in 

 the extreme, with simple pallial lines, strongly marked muscular 

 scars, particularly the anterior, which are complex, and, so far as I 

 can ascertain, edentulous, at any rate the examination of a very 

 large number of internal casts has failed to reveal the presence of 

 hinge teeth. In the place of the latter the cardinal margins were 

 very much thickened, particularly at the extremities, and in all 

 probability this was accompanied by an internal ligament. In 

 the face of these combined characters the reference of the species 



* Named in honour of Samuel Stutchbury, the first Government 

 Geologist of New South Wales, as it then was. 



