178 CARBONICOLA, ANTHRACOMYA, AND NAIADITES. 



from the shell under description. The shale in which A. subparallela occurs is 

 lithologically distinct from that in which the other forms are found. 



I had figured two specimens, PI. XVII, figs. 1 and 2, from the cabinet of 

 Mr. Joseph Wright, of Belfast, and remarked at p. 88, a7ite, that my attention 

 had been drawn to the resemblance between this shell and those of the genus 

 Anthracomya ; and since that time I have been able to study the original specimen 

 on which the species was founded, now preserved in the Museum of the Geological 

 Survey, Jermyn Street, and some more specimens from Ballycastle in the Belfast 

 Museum, two of which have the hinge exposed. This material came into my 

 hands after the letterpress of my observations on Anthracomya was printed off, 

 but I mentioned the fact that I had come to the conclusion that the shell really 

 belonged to that genus in a note on the page of explanation to PI. XVII. 



I now re-figure the original type by the kind permission of Sir A. Geikie, and 

 a specimen showing the greater part of the hinge by the permission of the 

 authorities of the Belfast Museum. The hinge, it will be noted, differs from that 

 of ^. modiolaris in not possessing an elongated posterior lateral tooth, so that this 

 character cannot be considered typical of the genus. I have not met with A. sub- 

 paraUela in the beds at Hollywood, near Belfast, where Modiola Macadamii occurs. 



This species resembles more nearly A. punctata than any of the others, but is 

 more convex, the lateral constriction is better marked, and the lines of growth 

 are somewhat oblique to the long axis of the shell. 



There is a fine slab of this species in the Geological Survey Collection at Dublin 

 from Slieve Gullion, Derry, showing a large variety of shells in various stages of 

 growth. In the younger shells the oblique sulcus is more marked. 



Baily (' Figs. Char. Brit. Foss.,' 1875) evidently considered all the forms 

 described by Portlock as one, for he figures M. subparallela, and in the text 

 (p. 114) unites it with Macadamii of Portlock and its varieties. 



Keyserling and Eichwald both referred specimens from Russian Carboniferous 

 beds to Portlock's species, but altered the generic name to Cardinia. 



A figure is given by Keyserling (op. sup. cit.), and this differs somewhat in 

 contour from Portlock's type. Eichwald's description is short, and would do 

 for A. siibparallela. 



Naiadites modiolaris (p. 131). — To the localities for this shell should be added 

 the roof of the 2-foot 9 seam, Galli Colliery, and the roof of the 4-foot seam, 

 Bwllfa Colliery, South Wales. 



N. carinata also occurs in the latter bed. 



