440 CARBONIFEROUS LAMELLIBRANCHIATA. 



Autero-postcriorly . . . .77 mm. 



Dorso-ventrally . . . . . 26 ,, 



from side to side (estimated) . . . 15 ,, 



Localities. — England : the Carboniferous Limestone series of Lowick, 

 Northumberland; Carboniferous Limestone, Derbyshire (specimens in the Wood- 

 ■\vardian Museum) ; Halkyn Mountain, North Wales ; Middleton, near Wirks worth. 

 Scotland : the Upper Limestone series of Thornliebank and Bathgate ; Lower 

 Limestone series of Hairmyres and Ardross ; Calciferous Sandstone series, 

 Encrinite bed, east of Pittenweem, Fife. Ireland : Desertmartin, co. Derry ; 

 Aghaloo, CO. Tyrone. 



Ohser cations. — Phillips erected the species Solcmya vrimceva upon certain 

 shells from Northumberland, stated to be in his own collection, and in the 

 Yorkshire Philosophical Society, and the Natural History Society of Newcastle-on- 

 Tyne. The type specimen seems to have been in his own collection, and is lost.^ 

 There is very little doubt, however, owing to the preservation of the unfigured 

 shells in the public collections to which he refers, as to the identity of the species, 

 of which the description, though meagre, and the figure, though poor, are also 

 sufficiently definite to enable the species to be preserved. Li 1843 Portlock 

 redescribed the species {op. cit.), quoting Phillips's diagnosis; and his type, 

 though unfortunately not figured, is preserved in the Museum of the Geological 

 Survey, Jermyn Street, and I am permitted by the kindness of Sir A. Geikie to 

 re-figure the specimen, a very fine and well-grown example, PI. L, fig. 2. 

 In the same year de Koninck described the same species under the name 

 S. Puzosiana. At that time he did not discuss its affinities ; but in his second 

 great work (in 1885, loc. cit.) he saj^s " Cette belle espece, que j'ai cru devoir 

 dedier a Puzos, . . . se distingue facilement des 8. p'imseva, J. Phillips, et 

 sagenaria, P. de Ryckholt, par sa grande taille, par sa forme relativement plus 

 allongee, et par le parallelisme de ses bords cardinal et ventral." The average 

 measurements given by de Koninck are — " length 55 mm., height 24 mm., 

 thickness 12 mm." 



It would be thus apparent that Portlock's shell is much larger even than 

 de Koninck's, and that the comparative dimensions are practically identical in 

 both cases. Judging from the dimensions of Phillips's figure, one cannot quite 

 understand de Koninck's "attitude," for the figure measures antero-posteriorly 

 37'5 mm., dorso-ventrally 15 mm., or as 5 : 2. This multiplied by 11 gives 55 : 22, 

 showing comparative measurements not very far from those of de Koninck's 

 species, and is in contradiction to his statement that 8. Puzosiana is relatively 

 more elongate than 8. primseva. 



1 See page 19, foot-uote. 



