98 DEVONIAN FAUNA. 



slightly convex, of whicli that over the siphuncular area is the broadest ; the whole 

 crossed by occasional transverse foliaceous ridges or flounces, presenting on each 

 interspace a face convex towards the apex. Three or four smaller but similar 

 transverse foliaceous threads between each of these major flounces. 



Size. — A fragmentary specimen is about 28 mm. in ventro-dorsal, and 17 mm. 

 in transverse diameter. 



Locality. — Wolborough. There is a well-preserved fragment in the Museum 

 of Practical Geology, and a larger but less distinct example in the Torquay 

 Museum. 



BemarJcs. — I have not been able to identify these specimens with any other 

 Devonshire species. They evidently are very nearly allied to G. tredecimale, 

 differing chiefly from it in the much larger number of ribs, especially on the 

 dorsal side, the greater curvature of the shell, and the general fineness of the 

 markings. In the extremely foliaceous character of the transverse ridges the 

 species presents an approach to G. fimhriatum, Phillips, though definitely sepa- 

 rated from it by their rarity and alternating size, and by the prominence of its 

 longitudinal ribs. It is probable that all these major ridges were, both in this 

 species and G. tredecimale, originally foliaceous, and that this feature is only 

 obliterated by the accident of fossilization. 



These fossils appear, as far as can be judged from the material at our command, 

 to be the same as the shell described as C. Eifelense by d'Ai'chiac and de Verneuil. 

 This form is stated by its describers to be very similar to G. tredecimale, and 

 indeed the distinctions which they draw between the two are not found to be 

 constant even in the few specimens we have examined, and it is possible that the 

 former may prove to be only a variety of Phillips's species, as hinted by them. 

 At present, however, there is not sufficient evidence for uniting the two species. 

 It would appear that the fourteen ribs on G. Eifelense were counted on the back 

 of the shell, whereas the thirteen on G. tredecimale were counted all round. Hence 

 the former is described as having much more numerous ribs. This and the 

 difference in distance of the large transverse ridges are the separating features. 



G. tentaculata, Miinster,^ from the Bifel appears to agree exactly with the casts 

 of G. Eifelense in the British Museum. It is distinguished by the peculiar mark- 

 ings which Miinster describes thereon. Though he figures the siphuncle as distinct 

 from these, I am much inclined to believe that it is identical with them, and, 

 therefore, to regard his species as the same as ours. It is to be noticed that it 

 comes very near to the figure of G. nautiloideum (Phillips), with whicli indeed 

 G. Eifelense was united by Mr. Foord, though he now agrees with me in regarding 

 that shell as belonging to G. ornatum (Phillips). 



Sandberger treats G. ornatum as only a variety of G. Eifelense, or, as he calls 

 1 1839, Miinster, 'Beitr.,' pt. 1, p. 34, pi. ii, figs, 2 a—c. 



