400 CARBONIFEROUS LAIMELLIBRANCHIATA. 



Stebden, Yorkshii'e ; Limestone in brook south of Sellet Hall, Westmoreland; 

 Park Hill and Castleton, Derbyshire; Poolvash, Isle of Man; Lowick, North- 

 nmberland. The Middle White Limestone, Craig-Fawr, and tlie Upper White 

 Limestone, Llanymynech, North Wales. Scotland : Upper Limestone series. 

 Shale, below tlie Linn Spout Limestone, Linn Spout, Dairy, and Craige, near 

 Kilmarnock ; Lower Limestone series, shales below the Beith Limestone of Hind 

 Og Glen, Dairy ; shale above the Limestone at Ravenscrag Castle, Fife. 



Ohservatlons. — This species, referred originally to Cypricardia, w\as erected 

 upon a single specimen from the limestone of Vise, Belgium, by de Kouinck, oj). 

 cit. M'Coy redescribed the species under Sangumolites from British localities 

 very thoroughly and accurately, and drew attention to its peculiar characters; 

 but he appears to have met with only small shells, in which the surface markings 

 are much finer and irregular than in full-grown examples. I have had the 

 opportunity of examining the shells from Craige and Lowick, in the Woodwardian 

 Museum, Cambridge, on which this description was founded. 



I cannot but think that the GervilUa incoiispicua of Phillips is described from 

 a specimen of 8. striato-lamellosiis ; but the original has completely disappeared, 

 and it is better to allow the name to drop altogether; moreover the figure is 

 taken from a very incomplete example. Shells of this species from Castleton are 

 much less rugged than the full-grown example, PI. XLIII, fig. 11 ; but they 

 attained full adult dimensions in this locality. Colour bands are often preserved 

 on Castleton specimens, especially those obtained from the Odin Quarry. Scottish 

 examples, as might be inferred from their occurrence in shales, are much more 

 delicate, their shells thinner and of smaller size. Specimens, however, from all 

 the localities and in all stages of growth possess the peculiar trigonal posterior 

 end. 



I am inclined to think that in his later work de Koninck has referred 

 3^oung and half-grown specimens of 8. striato-lameUosus to new species. Of 

 these 8. vcxillum and 8. tahulatus are examples, both of which possess the 

 peculiar-shaped posterior end. It is to be noted, however, that, although he 

 describes the posterior end of 8. striato-lameUosus as " doublement tronquee " in 

 his first diagnosis, and with a misprint of " inferieure " for " posterieure " in his 

 later work, in the figure accompanying the latter a false contour is given to the 

 shell, which is incomplete behind, but has a regularly rounded margin drawn in. 



De Koninck states that S. striato-lameUosus has greater resemblances to 

 8. transcersus, another of his species, than any other, but difi'ering in having its 

 surface lamellated; and its line of growth stronger, and being relatively broader 

 from side to side. It possesses the peculiar bitruncate trigonal posterior end 

 characteristic of 8. striato-lameUosus. De Koninck states that he has compared 

 the Belgian specimen with White and Whitfield's Cypricardia rigida, from Iowa, 



