ANTHRACOMYA WARDI. 107 



specimen from the Collection of Mr. George Wild, fig. 18, show what I take to be 

 younger forms of the same species, the general shape of the shell being the 

 same, but young forms have a sharper oblique ridge and radiating lines on the 

 posterior slope of the shell above the oblique ridge. The typical blunt, truncate 

 posterior end, sinuous above, is common to both the young and adult state. 



M. d'Eichwald's figure of Modiolopsis tenera differs from Anthracomya Wardi in 

 being shorter, whilst no mention is made of the oblique compression and blunt 

 ridge, though the outline of the posterior border is very similar. 



The specimen from the Holly Lane Shale at Whitfield (PI. XV, fig. 20) possesses 

 the characters of the young shells. The study of a series has convinced me that 

 the shell that I described in 1893 (op. cit. supra) as Anthracomya angusta is only 

 a very young specimen of A. Wardi. I refigure this specimen on PI. XV, fig. 12; 

 and, from a closer examination of the matrix, doubt its having come from the 

 Hard-mine bed, several shell-bearing beds being mixed on the tip heap where I met 

 with the specimen. I have figured on PI. XIII, figs. 13, 15, and 16, two shells 

 from the coal shale of Wakefield, which I take to belong to this species. The 

 extreme posterior end has not been preserved ; but if one may judge from the 

 direction which the lines of growth take in the posterior part of the shell, it 

 would correspond with that possessed by the type. It is possible that they may, 

 in the future, when more specimens are obtained, be shown to be distinct. 

 PI. XIII, fig. 15, I have with hesitation referred to this species ; it is from the 

 roof of the 8-foot coal in the coal-measures of Durie, Fife, and was given me by 

 Mr. Kirkby, of Leven. It has a certain resemblance to the shell from Wakefield, 

 but it is unlike every other example in having that portion of the shell above the 

 oblique ridge evenly gibbous. There are, however, in this place obscure radiating 

 lines, and the posterior end, not quite perfect, was hardly so truncate as in the 

 type; but on comparing this figure w r ith that of fig. 19, PI. XV, a close resem- 

 blance will be noted. 



There is a fairly typical specimen of this species in the Geological Survey 

 Collection from Burrs, near Bury, Lanes, labelled Sanguinolites, sp., in Mr. Salter's 

 handwriting. It is in quite a different matrix from the specimens labelled 

 Anthracomya saiiguinolaris (MS.), and referred to at p. 35 of the ' Memoir of 

 Geol. Surv.,' " The Geology of the Country round Bolton-le-Moors," which I 

 identify as A. Williamsoni. 



I noted a specimen in the museum at Dresden from the Grube Hannibal, near 

 Bochum, wdiich I believe to belong to this species. In Great Britain Anthracomya 

 Wardi is rare, even in the beds in which it does occur, and has a very limited 

 horizontal distribution. 



