Frof. T. Rupert Jones — South Wales Entomostraca. 217 



form is similar to Prof. Williamson's TJnio Phillipsii, from the 

 Upper Coal-incasnros at Ardwick, near Manchester, dcscriljed by 

 him in the " Pliil. Mag.," 183G, p. 241. It is the same also as Prof. 

 Phillips's Unio Unguiformis, " Sih Syst.", p. 88, and Mr. Binney's 

 Modiola (?), " Manchester Lit. Phil. Soc. Trans.", vol. xii. p. 221. 

 Prof. Williamson has lately favom-ed mo with a sketch of this shell, 

 and with a piece of the Ardwick shale. The same form occurs plen- 

 tifully in the Coal-shales of other places, and has been labelled 

 Anthracomya {Unio) Pldllipsii in the Museum of the Geological 

 Survey. In 1861 Mr. Salter instituted the genus Anthracomya for 

 such shells as these, of which there are several forms that " havo 

 oscillated hetween Avicula and Modiola, and even Unio" ("Iron-ores," 

 etc., p. 230). Prof. King's Anthracosia had already taken in the Unio- 

 like forms, and Mr. Salter afterwards proposed Anihracoptera^ for 

 the reception of the obliquely angular forms, somewhat like Mijalina 

 and Dreissena. 



Fig. 1, PI. IX., represents the Anthracomya, so abundant in the shales 

 under notice ; specimens like Fig. 18 are rare. The shell is concen- 

 trically wrinkled, somewhat irregularly, and the ridges are modified 

 by pressure. The surface is marked with fine lines parallel to the 

 ridges. Fig. 3, in plate 2 of the " Iron-ores, etc.," Part iii., may be 

 a small Anthracomya Phillipsii, but it is rather too narrow. 



§ 2. Estheria Adamsii. — Together with the above we find several 

 very similar shells, concentrically ridged, but marked all over with 

 microscopic pittings, like the pattern of a thimble-top on a very 

 minute scale — an ornament very unusual in Molluscs, but common 

 in Estheria {E. DunTceri and E. Hislopi, Baird, for instance). The 

 punctation difiers from that of the little Mollusc, Lepton squamosum, 

 in being far smaller and very much more closely set. The best pre- 

 served specimen of this Estheria-like shell is more like Anthracomya 

 Adamsii (Salter, " Iron-ores, etc.," Part iii., p. 230, pi. 2, fig. 7) in 

 shape than A. Phillipsii, being less oblique than the latter, and 

 having a longer hinge-line. The specimens, however, are all too 

 much crushed to be taken as perfect types of form. 



In some slabs of shale there are films of whitish minute network, 

 which appear to have resulted from the decomposition of these punc- 

 tate shells ; whilst the common Anthracomya have become changed, 

 sometimes into white calcareous shells, but are usually brownish, 

 sometimes minutely granular, but not reticulate. 



The outline of the reticulate valves, when perfect, or nearly so 

 (Fig. 1), closely approaches that of Estheria striata, var. Beinertiana 

 (Monog. Foss. Esth., p. 25, pi. 1, fig. 13). The superficial orna- 

 ment, however, constitutes a specific difference. In other cases the 

 valve is narrower, and has a shorter hinge-line (Fig. 2) ; but it is 

 difficult to determine if this be an original shape, or if it be due to 

 squeezing. 



I propose to register this large Estheria (more than an inch in 

 length), obliquely ovate in outline, with a long straight hinge, and 

 wit^ numerous concentric irregular ridges, and a general ornament 

 1 Quart. Journ. Geol. Soc, 1863, vol. xix., p. 80. 



