1G0 DEVONIAN FAUNA. 



ventral valve there appears to be a median septum, which, taken together with 

 the punctated surface, indicates that it belongs to Spiriferina. 



The present shell is the Devonian representative of the race which includes the 

 Silurian Sj). elevata, Dalman, 1 sp., and the Carboniferous and Permian Sp. cristata 

 (and its variety octoplicata). 



As given by Davidson, Sj). elevata has a much wider area and a less incurved 

 beak, Sp. sulcata 2 fewer ribs and sometimes sharper wings, and Sp. crista 3 closer 

 transverse lines and fewer ribs. These forms Davidson does not refer to Spiriferina, 

 but retains in Spirlfera. 



On the other hand, I can see no differences whatsoever between it and his 

 Carboniferous figures of Sp. cristata, var. octoplicata, except that the ribs seem 

 slightly less numerous, and a minute median depression is seen on the fold. The 

 small rib on the sinus is equally visible both in the Carboniferous and the Devonian 

 shells. The Permian Sp. cristata* itself has fewer ribs and a more lofty umbo. 

 Thus it seems that the present shell is inseparable from the Carboniferous form, 

 whatever may be its relation to the Silurian and the Permian species. 



Affinities. — Sp. Zeilleri, Barrois, 5 closely resembles it, and may possibly even 

 prove identical ; but its lamellae seem fewer, and its fold not biplicated. 



In Sp. aculeata, Schnur, 6 the transverse lines seem broken into long fringes 

 instead of simply showing puncta. With regard to that shell it may be noted 

 that Holzapfel 7 places Spiriferina insculpta, Phillips, sp., as a synouym of it, so 

 far as regards the Devonian form described by Davidson 8 from Lummaton. 

 Whether this Lummaton shell is separable from the Carboniferous type of 

 Sp. insculpta, and whether it possesses the distinctive longitudinal lineation which 

 exists on the lamellae of Sp. aculeata, are questions I venture to think are not yet 

 proved in the affirmative ; but in any case two points have been overlooked 

 by Herr Holzapfel, viz. (1) that the Lummaton species is a Spiriferina, not a 

 Spirifera ; and (2) that if it is not Sp. insculpta, Phillips, it certainly is Sp. pulchella, 

 Sowerby. 9 The latter point appears clearly on the examination of Sowerby's type 

 in the museum of the Geological Society. If, therefore, Herr Holzapfel is right in 



1 1807, Davidson, 'Brit. Foss. Brach.,' vol. iii, pt. 7, p. 95, pi. x, figs. 7 — 11. 



2 Ibid., vol. iii, pt. 7, p. 91, pi. x, figs. 4 — 6. 



3 Ibid., vol. iii, pt. 7, p. 97, pi. x, figs. 13—15. 



4 1858, ibid., vol. ii, p. 17, pi. i, figs. 37—40, 45, 46; and pi. ii, figs. 43—45. 



5 1882, Barrois, ' Mem. Soc. Geol. Nord,' vol. ii, p. 256, figs. 13, 13 a, 13 b. 



6 1854, Schnur, ' Palaeontographica,' vol. iii, p. 203, pi. xxxiv, figs. 2 a, b. 



7 1895, Holzapfel, 'Abhandl. k. Preuss. Geol. Landes.,' n.s., pt. 16, p. 250. 



s Holzapfel quotes Davidson thus : — " 1864, Spirifer insculptus, ' Brit. Dev. Brach.,' Supple- 

 ment, pi. i, fig. 32." This reference requires to be thus corrected: — "1882, Spiriferina insculpta, 

 ' Brit. Dev. Brach.,' Supplement, pi. i, fig. 32." 



9 1810, Sowerby, ' Geol. Trans.,' ser. 2, vol. v, pt. 3, pi. lvii, fig. 8. 



