Mr. Gray on Melania Setosa. 253 



of the ribbed coat, and resembles the inserted portion of the first 

 spiniform ray of the dorsal fin of the Squalus Acanthias {^pinax 

 Cuvier), of Balistes, and of several other Fishes, we may conclude, 

 I think safely, that if it be not really such a bone, it is at all 

 events a partially exserted one, and such as we are not likely to 

 meet with, either among the Mammalia, or in any other class, ex- 

 cept Fishes. There is a somewhat similar lanceolate, arcuated, 

 three-sided, and longitudinally ribbed bone, well known in the 

 Lias, which has one and sometimes two rows of conical, curved 

 teeth arranged along its concave side ; this seems to connect the 

 one before us with the long bony and toothed spine upon the tail 

 of the Sting-Ray (Raia Pastinaca^ Linn.) and, like that, is much 

 more solid than Fishes' bones generally are ; but as no attached 

 bones have been yet discovered with these fossils, it is not possible 

 to refer either of them to any known Genus. 



The circumstance of that before us having occurred in the Coal 

 Formation, is extraordinary ; its accompanying apparently land 

 vegetables can have very little weight, for Bivalve Shells are by 

 no means rare, similarly situated in the Carboniferous Strata. The 

 lateral curvature, and some irregularity in its form, seem to have 

 arisen from distortion produced by pressure. 



The accompanying figure, Plate VIII. f. 9 is of the full size 

 of the specimen, a small portion of the larger end only being 

 omitted. 



Art. XXXV. On the structure of Melania setosa. By 

 Mr. J. E. Gray, M.G.S. 



In the last number of the Quarterly Journal of Science, Mr. Swain- 

 son, has described a new shell,^ under the above name, which he 

 observes has attracted considerable attention in the Conchological 

 world, from the peculiar bristles-like processes, which are sheathed 

 in its tubular spines ; and Mr. Swainson has not a little added to 

 this attraction, by his description of the shell, in which he ob- 



