SALPINGOSTOMA. 67 



? 1886. Bellebophon Sakdbeegeei, Maurer. Faun. Eechtrhein. Unterdev., 



p. 20. 

 1891. — MACKOMPHALUS, WMclhome. Dev. Fauna, vol. i, p. 327, 



pi. xxxi, figs. 10, 10 a. 



Description. — Cast of shell rather large, subglobose, rather flattened, hori- 

 zontally symmetrical. Spire elliptically coiled ? Whorls flattened on the back, 

 regularly and moderately convex round the upper and lower sides. Sinus-band 

 indicated by a central depression in the cast until it approaches the aperture, 

 where it rather suddenly rises into a rounded ridge. Umbilicus wide, curving 

 regularly round, continuously with the lateral curves of the whorl. Mouth 

 expanding rapidly to form broad transverse wings or expansions, so that the 

 diameter of the mouth is three times that of the height of the shell a short 

 distance behind it. 



8ize. — Height 40 mm. across the expanded mouth, 14 mm. across the 

 umbilicus near the mouth ; width through sinus-band 24 mm. 



Localities. — In the Barnstaple Athenseum are five specimens from Kingdon's, 

 Shirweli ; and in the Museum of Practical Geology two from the Pilton Limestone 

 of Marwood. 



Remarks. — Though our specimens are all casts, a very minute fragment of 

 shell remains on one of the figured specimens of them, and appears to show a 

 minute ridge-like ornament. 



This species is either identical with or very near akin to 8. macrostoma, 

 F. Romer ; our specimens do not show an unbroken circle in the expansion of the 

 mouth, perhaps simply on account of their imperfect condition, nor have they 

 so wide an umbilicus. 



Bellerophon macromphalus, F. A. Romer, has, according to his own figure and 

 description, a very much larger and flatter umbilicus with more numerous narrow 

 whorls ; but, as revised by Beushausen, it seems almost exactly to agree with the 

 present species. While all the material is confined to casts, it is hopeless to arrive 

 at certain conclusions, but it seems clear that B. macromphalus and B. macrostoma 

 are generically identical, and no reason seems assignable why they should not also 

 be so specifically. The South Devon shells which I described from Chircombe 

 Bridge show, I think, no difference from the North Devon fossils, except that 

 they are circularly coiled, and that they are sometimes rather more angulated 

 round the umbilicus — points which need not be indicative of specific distinction, 

 as neither of them seems constant. 



Affinities. — B. Gostariensis, F. A. Romer,^ is said to differ from S. macrostoma, 

 F. Romer, by its more involute and fewer whorls, the more sudden widening of 



1 1855, F. A. Romer, ' Beitr. Harzgeb.,' pt. 3, p. 14, pi. iii, fig. 17. 



