BELLEROPHON. 65 



do not admit of a complete description. The matrix shows that they belong to 

 the Marwood series. The rate of increase of the whorls is very slow, and in none 

 of them is there any sign of any labial expansion. In one of the specimens there is 

 a slight indication of a central depression on the back ; and in another (which is 

 figured on PI. VIII) there is an equally slight suggestion of a central keel. In the 

 latter specimen there also appears an oblique flattening of the back on each side 

 of the median line, which is not usually seen. In one or two cases very faint and 

 doubtful marks exist, which possibly indicate that it was ornamented in the style 

 of B. lineatus, Sandberger.' 



These appear to be the shells described by Phillips as B. glohatus, Sow.,^ from 

 "Marwood, Pilton, Brushford, &c.," though in his figures the umbilicus seems larger, 

 and there seems some indication of ornament. The central of his six figures is 

 the most like our shells. They were separated from B. glohatus by M'Coy on 

 account of their small umbilicus, and they also differ from it in the slow rate of 

 increase of their whorls. Whether they are distinct from all the accompanying 

 shells whose ornament is known cannot at present be positively asserted. They 

 bear some likeness to young or imperfect specimens of S. ? macromphalus of the 

 Pilton beds, but difier in being smaller, and in having a smaller umbilicus, and no 

 signs of any labial expansion. 



They also approach in general shape B. labyrinthodes, but seem to have more 

 slowly increasing whorls. 



4. Belleeophon ? sp. Plate VIII, fig. 7. 



Description. — Cast of shell small, discoid, oval, flatfish. Spire consisting of three 

 rapidly increasing whorls, deeply sunken, probably very similar above and below. 

 Whorls vertically narrow, horizontally wide, convex (the convexity being much 

 greatest on the back), slightly involute (the outer whorl enveloping one-third of 

 the whorl within). Umbilicus open, with a spiral concavity formed by the suture. 

 Mouth slightly expanded. Margin of lip convex. Back deeply and evenly 

 convex, not keeled. 



Size. — Height about 4 (?) mm., width 6 mm., depth 9 mm. 



Localities. — Two specimens from Vicarage Well, Pilton, are in the Barnstaple 

 Museum. 



Remarks. — These specimens are very indistinct and puzzling. They give so 



^ 1896, Whidborne, ' Dev. Fauna,' vol. i, p. 321, pi. xxxi, figs. 3 — 6. Holzapfel calls this species 

 £. striatus, Bronn, 1839, but Fleming, in 1828, described a Carboniferous form like B. elegans under 

 the same name, and bis description is definite, though unaccompanied by a figure. 



2 1839, Sowerby, in Murchison's ' Sil. Syst.,' p. 604, pi. iii, fig. 15. 



I 



