GYROCERAS. 95 



mended, it would seem that this feature has been rather obscured than emphasised 

 by that operation, the effort of the manipulator having naturally been to restore 

 the fossil to a supposed uniformity. 



In the ' Geol. Mag.' of January, 1889, I described this shell under the name of 

 Gyrtoceras majesticum. At that time I had not discovered that the G. ornatum of 

 Phillips was distinct from that of d'Archiac and de Verneuil, and it was clear that 

 the present species was different from the English specimens of the former shell, 

 that accompanied it. Subsequently, however, a closer examination has convinced 

 me that de Verneuil' s identification of Phillips's specimen with the German species 

 was incorrect ; and, moreover, a comparison of the German specimens in the British 

 Museum with the present fossil have proved that it is really only the cast of a very 

 large example of that shell. Unlike some of the adjacent species, the large nodes 

 of the outer shell are not reproduced upon the cast. In its measurements, rate 

 of tapering, and character of coiling it almost exactly agrees with the figure 5 6 of 

 d'Archiac and de Verneuil, and there is no reason to doubt its identity. Added to 

 this the matrix agrees closely in character with that of the German specimens in 

 the British Museum, and Mr. Btheridge and others agree with me that there is 

 every reason to suppose that it must have been a foreign specimen placed by 

 Mr. Godwin-Austen with his Devonshire specimens for reference, and that so it 

 accidentally became incorporated in his Wolborough Collection. As this specimen 

 is the only evidence of the true G. ornatum, Goldf ., from these localities, it appears 

 that the name must be removed from the present list. The plate, however, was 

 drawn before I had arrived at this conclusion, and I have therefore inserted it, as 

 it will be useful for comparison, especially as the figures given by the foreign authors 

 are of fragmentary shells. Mr. Foord informs me, however, that the present species 

 occurs at Mudstone Bay, and is represented in the British Museum by specimens 

 from that locality which show its characteristic ornamentation. There is also a 

 large series of German specimens in the British Museum, some of which are still 

 finer than this figured one, and show more definite indications of tubercles. 



Chjroceras nudum, Barrande, presents much similarity to this species, to which 

 it may belong. In two of his figured specimens, however, the spire seems more 

 completely coiled, and at the orifice (which I have not observed in the German 

 shells) are two small lateral protuberances. The surface of the shell is not given, 

 so that it is impossible to judge whether there may be a specific difference in 

 ornamentation. In G. alatum, Barrande,^ the whorls are entirely discontiguous, 

 and much more rapidly increasing. 



G. validimi, Hall,^ has much narrower septa. 



1 1865, Barrande, ' Syst. Sil. Boheme,' vol. ii, p. 162, pi. xliv, figs. 8—18, and pi. ciii, figs. 15— 

 20, fit. F. 



2 1879, Hall, ' Pal. N. Y.,' vol. v, pt. 2, p. 385, pi. xlix, fig. 2, and pi. c, fig. 1. 



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