158 DEVONIAN FAUNA. 



shire it was first described under the name Atrypa unguiculus, Sowerby, but was 

 united to the Carboniferous Sp. Urii by Davidson, and no doubt correctly so. 



The muscle-scars seen in some of our specimens are long and very narrow, 

 and there are no dental plates or median septum. Thus they appear to fall 

 within the group Martinia, to which Davidson doubtfully referred them, though 

 they certainly bear in some aspects a resemblance to Ambocflelia, the value of 

 which cannot be measured until the spires are discovered. None of our specimens 

 show the surface, but Davidson has figured a Carboniferous example with 

 numerous coarse spines. 



In size the Devonian fossils somewhat exceed the dimensions of the Car- 

 boniferous shell as given by Davidson. 



Affinities. This species seems widely different from the Lummaton Sp. infima, 

 mini, 1 which I suspect belongs to Amloccelia. 



I think also that Holzapfel 2 is right in separating it from Sp. inflata, Schnur, 3 

 which was joined with it by Kayser ; 4 though my strong impression is that both 

 the shells he figures under that name should be referred to other species. 



5. SPIRIFERA MESOMALA, Phillips. Plate XIX, figs, 8, 9?9a?96? 



1841. SPIBIFERA MESOMALA, Phillips. Pal. Foss., p. 78, pi. xxxi, fig. 137. 



Description. Shell small, moderately transverse, with apparently rounded 

 wings. Beak moderately elevated and incurved. Ventral sinus wide, concave, 

 with two or three indistinct lineations, not breaking its smoothness. Lateral ribs 

 simple, prominent, rounded, distant, about ten on each side ; without signs of 

 transverse markings. 



Size. A specimen measures about 6 mm. wide. 



Locality. One specimen is in my Collection from Saunton Hotel, and one or 

 two in Mr. Hamling's Collection from Snapper Quarry. A very imperfect specimen 

 in Mr. Upfield Green's Collection from Sloly may belong to this species, but 

 1 s perhaps more likely to be a small worn example of Sp. Verneuilii, var. 

 Barumensis. 



Remarks. Phillips's description of his species is so incomplete that Davidson, 



1 1893, Whidborne, ' Dev. Fauna,' vol. ii, p. 108, pi. xiii, figs. 13. 



2 1895, Holzapfel, ' Abh. k. Preuss. Geol. Laudes.,' n. s., pt. 16, p. 253, pi. xi, fig. 20 (?) ; and 

 pi. xvii, fig. 6. 



3 1854, Schnur, ' Palaeontographica,' vol. iii, p. 211, pi. xxxvii, fig. 2. 



4 1871, Kayser, ' Zeitsch. Deutsch. Geol. Gesell.,' vol. xxiii, p. 584. 



