58 CARBONIFEROUS LAMELLIBRANCHIATA. 



Localities. — England: the Carboniferous Limestone of Clitheroe, Lancashire; 

 Hill Bolton and Settle, Yorkshire; Castleton, Kniveton, and Glutton Dale, 

 Derbyshire ; Lowick and Redesdale (Redesdale Ironstone), Northumberland. 

 Scotland : Lower Carboniferous of Eskdale, Dumfriesshire ; Pathhead, Haddington- 

 shire. Ireland : Carboniferous Limestone of Clane, co. Kildare ; Woodlands and 

 Malahide, co. Dublin ; Clogherbrian, co. Kerry ; Banteer, co. Cork. 



Observations. — The type specimen is preserved in the Sowerby Collection, 

 Natural History Museum, South Kensington, and it is re-figured in PI. X, fig. 6. 

 It is the left valve of a small specimen, and has lost a part of the posterior 

 superior angle, but shows the depressed anterior ear. The ribs are closer and 

 more numerous than often occurs. De Koninck completely mistook the shell, the 

 specimen figured and described by him as Aviculojpecten granosus, Sow., probably 

 not belonging to the same genus. The shell does occur in Belgium at Vise, and 

 was described under the name of A. nodulosus, de Koninck. This author describes 

 the ears of his A. granosus as being about of equal size, which is not the case. 

 De Koninck criticises Phillips's figured specimen of Pecten granosus, and perhaps 

 with some justice, unless, perchance, it was imperfect in the region of the ears. 

 The description, however, meagre though it be, rather agrees with that of 

 Sowerby's shell. Unfortunately the type has disappeared, so the matter cannot be 

 now determined. 



I have been fortunate enough to obtain specimens with both valves in contact, 

 and one specimen showing the hinge-line (PI. X, fig. 3). The right valve is almost 

 flat, as de Koninck states to be the case in his shell, A. nodulosus. There is a 

 certain amount of variation in the ornamentation of different specimens of this 

 species, owing to the non-development of secondary or tertiary ribs, and the 

 strength and number of the nodular swellings on them. Judging from the shape 

 and condition of the very young shell of P. granosus as shown by the deeply 

 marked line of growth in the specimen drawn in PL X, fig. 2, Amcidoyectcii blandus, 

 de Koninck, represents this condition. The shape, alternate nodular ribs, and 

 length of hinge-line are identical. I have therefore placed this specific name in 

 the list of synonyms. De Koninck's type was obtained from Vise, the locality of 

 A. nodulosus, de Kon. P. granosus is distinguished from P. eximius by the 

 irregularity of the nodes on the ribs and their distance apart. These nodes are 

 very numerous and close in the latter species, and its shell is altogether of less 

 rugged character than that of the former. 



