SPIRIFERA. 157 



it is difficult to say from our specimens how many of the central ribs should be 

 counted as belonging to it. 



I am inclined to think it possible that this form may be only a variety of Sp. 

 Bouchardi, Murchison. In Murchison's figure the ribs seem stronger and more 

 numerous (those on each side of the sinus being very strong), and the transverse 

 lineation stronger and more regular. These slight differences may, however, 

 partly be explained by the better state of preservation of Murchison's specimen. 

 Moreover our Devonshire shells, none of which are sufficiently well preserved 

 to show the transverse ornament clearly, display much variation in the number 

 of the ribs and other points. On the other hand, specimens of Sp. Bouchardi 

 from Ferques in the Davidson Collection are less like them, and all appear to 

 differ in their more angular shape, their definite folds, and their very strong 

 lineations. 



Phillips regarded Sp. obliterata as allied to Sp. speciosa, Schlotheim ; 1 but 

 Dr. Barrois, to whom I have shown a photograph of it, sees no reason for 

 supposing it identical. It seems to be distinguished from that species, and from 

 its ally or variety Sp. paradoxa, Schlotheim, 2 by the bifurcation of its fold and 

 sinus, and the more definite grading of its ribs. 



Sp. mucronata, Conrad, as given by Sandberger, 3 and Sp.phalsena, Sandberger,* 

 seem to be less transverse, and to have stronger and more equal ribs. 



4. Spirifera (Mautinia?) TJsii, Fleming. Plate XIX, figs. 5 — 7. 



1828. Spieifeea Ukii, Fleming. Brit. Anim., p. 376. 



1840. Atestpa unguicultjs, Soioerby. Geol. Trans., ser. 2, vol. v, pt. 3, pi. liv, 



fig. 8. 



1841. Si-IEIFEKA tTNGUicULUS, Phillips. Pal. Foss., p. 69, pi. xxviii, figs. 



119 a—f. 

 1864. — Ueii, Davidson. Brit. Foss. Brach., vol. iii, p. 41, pi. iv, 



figs. 25—28. 

 1884. — (Mabtinia ?) Ueii, Davidson. Brit. Foss. Brach., vol. v, 



p. 418. 



Localities. — Croyde, Braunton, Petherwyn, Top Orchard, Bradiford, Vicarage 

 Well Pilton, Frankmarsh, Upcott Arch Quarry, Ashhill Quarry, Wrafton Lane, &c. 

 Size. — Height about 9 mm.; width about 13 mm. 

 Remarks. — This is a very common and characteristic species. From Devon- 



1 1813, Schlotheim, ' Taschenbuch f. Mineral.,' vol. vii, p. 52, pi. ii, fig. 9. 



2 Ibid., p. 28, pi. ii, fig. 6. 



3 1889, F. Sandberger, ' Entw. Unter-Abtheil. Dev. Systems Nassau,' p. 104, pi. iii, fig. 2. 



4 Ibid., p. 105, pi. iii, figs. 3, 3 a. 



