108 CARBONICOLA, ANTHRACOMYA, AND NAIADITES. 



7. Anthb-acomya fumila, Salter. Plate XVI, figs. 2, 3, and 40. 



ANTnRACOHTA ruMiLA, Salter. 'Iron Ores of South Wales,' p. 230, pi. ii, 



fig. 10, 1861. 

 Non — Hind. Quart. Jouru. Geol. Soc, vol. xlix, p. 260, pi. x, 



figs. 17, 19, 28, 29, 1893. 

 — carinata (pars), Hind. Ibid., p. 273, pi. x, figs. 16, 16 a. 



Specific Characters. — The shell is transversely oblong, only slightly convex. 

 The hinge-line and ventral margins are almost straight and nearly parallel. The 

 umbones are small with depressed non-contiguous apices, situated within the 

 anterior third of the hinge-line; the lunule is narrow and elongate. The anterior 

 end is short, and somewhat pointed at its anterior superior angle. The posterior 

 end is bluntly rounded or truncate. There is an obtuse diagonal ridge which rises 

 in the umbones, and passes backwards and downwards to the posterior inferior 

 angle of the shell, above which the shell is compressed so as to become slightly 

 concave and expanded upwards into the posterior hinge-line. 



The Interior is not exposed in any of the specimens from South Wales. 



The Exterior. — The surface is covered with strice and lines of growth, more 

 marked and rugose at the ventral border ; periostracum wrinkled. 



Dimensions. — Fig. 2, PI. XVI, measures — 



Antero-posteriorly . . . . 17 mm. 



Dorso-ventrally . . . 8 mm. 



From side to side . . . .5 mm. 



Locality. — Mine over Three-quarter coal, No. G pit, Victoria, South Wales 

 Coal-field, and at Merthyr Tydvil. 



Observations. — This species is at present only known from the bed above the 

 Three-quarter coal of South Wales, which was the locality whence the original 

 specimens described by Mr. Salter were obtained. It is just possible that the 

 specimens I am able to figure, by the courtesy of the authorities of the Cardiff 

 Museum, are the originals, as they have in their possession the collection of the 

 late Mr. Adams, which Mr. Salter states contained his type. 



This species differs materially from any of the forms in North Staffordshire 

 that have come to my knowledge, being much more compressed than A. Williamsoni 

 and much more elongate than A. minima, the latter being the typical shell in the 

 Knowles ironstone, which Mi'. Salter gave; as the horizon for A. yi nulla. 



In my paper on the "Affinities of Anthracoptera and Anthroxomya" 'Quart. 

 Joui'ii. Geol. Soc.,' vol. xlix, p. 2<i ( .», 1 doubtfully referred some young specimens 

 ol A. Williamsoni and A. pulchra to this species, but from a study of the series 

 in the Cardiff Museum I have arrived at the conclusion that these forms are quite 



