72 CARBONICOLA, ANTHRACOMYA, AND NAIADITES. 



for the insertion of the ligament parallel to it, for the elongate lamellar teeth of 

 M'Coy, which are not indicated in casts, and are characteristically absent in the 

 hinges of G. aquilina, which I figure PI. IX, figs. 5, 9, 12 — 14. In the many 

 fragments exhibiting all parts of the hinge-plate which have passed through my 

 hands I have never observed any indications of lateral teeth, my experience com- 

 pletely coinciding with Professor King's original observations on this point. 



The diagnostic features on which I have relied for the identification of this 

 species are the shape of the anterior end and the umbones, and the obliquity of 

 the lines of growth, taken together with the wedge-shaped, flattened form of the 

 sides of the valves and the broadly channelled upper border, characters which are 

 well shown in Sowerby's original figure in Professor Prestwich's ' Geology of 

 Coalbrookdale.' 



It is quite possible that the original of Ure's shell may have belonged to the 

 species under discussion, but the shell itself is lost. The characteristic oblique 

 lines of growth are indicated in his figure, and Dr. John Young, of the Hunterian 

 Museum, Glasgow, showed me a specimen from the original locality which was 

 certainly G. aquilina. Fleming, however, who was responsible for the name 

 IJnio JJrei, Ure having unfortunately omitted any description of his form, describes, 

 in his ' History of British Animals,' the shell Unio JJrei as follows : — " Transversely 

 oblong, dorsal margin nearly straight, unequally striated by lines of growth ;" but 

 he considered that this shell was synonymous with Martin's Mya oualis, which 

 exhibits none of the characters of G. aquilina. In addition Ure's shell has been 

 erroneously referred to Sanguinolites by Sowerby (Prestwich, ' Geol. of Coalbrook- 

 dale,' vide supra, pi. xxxix, fig. 6) ; I say erroneously, because several Scotch 

 geologists inform me that no marine forms ever occur in Ure's original locality. 

 After all, on account of the confusion attaching to the history of Ure's shell, I 

 have thought it advisable to adopt Sowerby's specific name of aqu/ilmus in place of 

 the doubtful reference to Ure. I believe that Goldfuss's Unio atratus and possibly 

 his U. tellmarius may belong to Sowerby's species ; the former has the character- 

 istically shaped anterior end, but the oblique lines of growth are not shown, and 

 the latter is crushed. A series of specimens, however, from the neighbour- 

 hood of Liege, which I examined at Liege, Brussels, and the British Museum 

 (Nat. Hist.), labelled with these names, convinced me that the species were 

 identical. I have been in doubt as to the question of priority between Sowerby's 

 aquiliniis and Goldfuss's atratus. Bound copies of ' Petrefacta Germaniae ' bear 

 the date 1840, but the work came out in parts, commencing 1836. This coal- 

 measure shell appears on pi. cxxxi, and its description at p. 180 was issued in 

 the livraison dated " 1837". Prof. Prestwich's ' Geology of Coalbrookdale ' was 

 published in 1840, and Sowerby's description of coal-measure shells was issued 

 as an appendix to it ; but the paper was read before the Geological Society on 



