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 OC. aquilina, which I figure Pl. 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 C. aquilina. Fleming, however, who was responsible for the name 
Unio Urei, Ure having unfortunately omitted any description of his form, describes, 
in his ‘ History of British Animals,’ the shell Unio Urei 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 ovalis, which 
exhibits none of the characters of O. aquilina. In addition Ure’s shell has been 
erroneously referred to Sanguinolites by Sowerby (Prestwich, ‘ Geol. of Coalbrook- 
dale,’ vide supra, pl. 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 aquwilinws in place of 
the doubtful reference to Ure. I believe that Goldfuss’s Unio atratus and possibly 
his U. tellinarius 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 Liége, which I examined at Liége, 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 
aquilinus and Goldfuss’s atratus. Bound copies of ‘ Petrefacta Germaniz’ bear 
the date 1840, but the work came out in parts, commencing 1836. This coal- 
measure shell appears on pl. 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 
