ACTINOPTERIA PERSULCATA. 23 



from Pferliieit in the absence of a broad striated ligamental area, and strong cardinal 

 and lateral teetli. Right valve snbconvex ; surface with fine rays." Miller (' N. 

 Amer, Greol. and Pal.,' 188V>, p. 459) seems to have put a different interpretation 

 on this sentence, for he says Ad ino pterin is " distinguished from Pterinea by strong 

 cardinal and lateral teeth, and no striations on the hinge-plate." 



I have thought it well to remove the shells with radiating ribs referred by 

 M'Coy to Pteronites to Hall's genus, to which they are evidently very closely 

 related . 



P. semisulcatas, M'Coy, is evidently a cast of the interior, and hence the 

 peculiar markings and the absence of rays. Unfortunately P. ventrlcosus, M'Coy, 

 is lost, and I am unable to recognise the species in any shells which I have 

 examined . 



In 1854 M'Coy re-described his genus Ptero)df('s, and referred to it a P. .suh- 

 radiatm (Devonian) and P.persulcatus, a species founded upon a cast of the interior 

 of a left valve. 



"When describing a new species in 1873 (' Geol. Mag.,' vol. x, p. 344) Mr. R. 

 Etheridge, jun., sought to demonstrate the specific differences between the ribbed 

 forms referred to Pteronites by M'Coy and two new species described by himself, by 

 variations in the radiating ornamentation ; but unfortunately he did not recognise 

 that in at least two cases he was comparing the interior of the valve with the 

 exterior. I am only able to accept one of Mr. Etheridge's species, P. Jiuduosns. 



The late Dr. John Young, of the Hunterian Museum, has demonstrated that the 

 shells referred to Pteronites, M'Coy, possess a prismatic shell structure, and 

 considers that they have a strong affinity to the Aviculidie, in which family I have 

 placed the genus Actlnopffr'ui . 



AcTTXOPTKRiA PERSULCATA, M'Goy, sp., 1855. Plate IV, figs. 9—11 ; Plate V, fig. 14. 



? Lanistes eugosus, M'Coy, 1844. Synops. Garb. I'oss. Ireland, p. 76, pi. x, fig. 8. 

 Pteronites persulcatus, M'Coy, 1851. Ann. Mag. Nat. Hist., 2ncl ser., vol. vii, 



p. 170. 

 _ _ _ 1855. Brit. Pal. Foss., p. 480, pi. 3 f, fig. 1. 



— KEOULARis, B. Etheridge, jun., 1873. Geol. Mag., vol. x, p. 298, 



pi. xii, fig. 6. 



— PERSULCATUS, Etheridge, 1888. Brit. Foss., pt. 1, Palaeozoic, p. 276. 

 Tornqvist, 1896. Fossilfiihr. Untcrcarb. Siidvogeseu, 



Abb. geol. Specialkarte Elsass-Lothr., Baud v, Heft 

 5, pi. xvii, figs. 1 — 3. 



f^peclfir Ch(traeters.—'^\\e\\ of medium size, very inequilateral, equivalve, sub- 

 rhomboidally trigonal, triangularly convex. The anterior end is almost obsolete, 

 represented by a narrow compressed fold below the urabones. The lower border, at 



