GONIATITES. 79 



14. GoNiATiTES PENTANGULARis, Wliidhome. PI, VII, figs. 2, 2 a. 



1889. GoNiATiTES PENTANGULAEis, WMdh. Geol. Mag., dec. 3, vol. vi, p. 29. 



Description. — Shell small, flat, discoidal, hardly involute. Umbilicus very wide 

 and shallow, so that the spire is almost wholly exposed. Sides of whorls rising in a 

 curve from the whorl below, then horizontally flattened for about half their width, 

 then curving suddenly, and again flattened obliquely so as to meet in a simple and 

 sharp keel ; the section of the whorl being thus almost regularly pentagonal, or 

 heartshaped, only indented by the keel of the whorl next within. Surface of body- 

 whorl ornamented with a few coarse radiating ridges ; that of the inner whorls 

 with small but very prominent, simple, erect, thread-like striae, both of which start 

 almost perpendicularly from the base of the whorls and then curve regularly and 

 quickly back, so as to meet the keel at a very acute angle. 



Size. — About 13 mm. in height, 10 mm. in width, 4 mm. in depth. 



Locality. — Barton. A single fragmentary example in the Lee Collection is the 

 only specimen of this shell which I have seen. 



Remarks. — I am aware of nothing like it having been described by British or 

 foreign authors, except G. incertus, d'Arch. and de Vern.,' which has the ribs direct 

 instead of oblique, and G. Zorgensis, F. A. Rom.,^ which has much coarser and fewer 

 ribs, and is ventrally truncated. 



Although the specimen is very fragmentary, it appears so well characterised 

 and so distinctive that I do not hesitate to record it under a specific name. 



15. GONIATITES SERPBNTINITS ? Phillips. 



? 1839. GoKiATiTEs SEBPENTiNTJS, PUl. Geol. Tork., vol. ii, p. 237, pi. xx, figs. 



48—50. 

 1841. — — — Pal. Foss., p. 123, pi. li, fig. 237. 



Description. — " General figure planorbiform, discoidally involute, the inner 

 whorls exposed ; surface not distinctly traceable in this specimen ; section of each 

 whorl elliptical and slightly emarginate internally ; septa with hnguiform lateral 

 inflexions. Siphuncle ? 



" Locality. — Newton Bushel (?) " — Phillips. 



1 1842, D'Arch. and de Vera., ' Geol. Trans.,' ser. 2, vol. vi, pt. 2, p. 342, pi. xxvi, figs. 6, 6 a. 



2 1866, F. A. Eom., ' Beitr.,' pt. 5, p. 9, pi. xxxiv, figs. 9 a—e. 



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