622 



MISS JANE DONALD ON CAKBONIFEKOUS 



but it is clearly identical with the shell since described by M'Coy as 

 M. Verneuiliana, var. Jcenclalensis, of which there are some speci- 

 mens in the Museum from Kendal. Phillips thus describes the 

 shell : " Whorls angular, the upper ones tricarinate." I have 

 examined a great many specimens of this shell, and it is never 

 tricarinate. It has a broad, flatfish band, about the centre of 

 each whorl, which is solid on the body-whorl, but on some 

 of the upper whorls it is frequently hollowed in the centre, which 

 causes it to be formed of two small keels with a groove between them. 

 This band represents the sinus, and is shown on the specimen in 

 the Gilbertson Collection, where it is solid, and not grooved. 

 In some specimens below this band, there is occasionally a 

 strong angle on the body-whorl, which either appears just above 

 the suture on the upper whorls, or else is hidden by the whorl below ; 

 there is never any indication of a keel on the angle in any of the 

 specimens I have examined, and in many, especially in older speci- 

 mens, the angle is scarcely visible, the base being rounded, and this 

 is the case with the specimen in the Gilbertson Collection. 



With this shell is another, also from Bolland, but which is clearly 

 distinct from it. It strongly resembles the right-hand specimen of 

 pi. xvi. fig. 16, but is evidently not the original from which the 

 drawing was made, as it is larger and appears to increase more 

 slowly ; but the exact spiral angle of the figure could hardly be 

 accurately determined, as the specimen is so imperfect. This shell, 

 however, agrees better with Phillips's brief description, being 

 angular, and the upper whorls, which alone are preserved, are 

 tricarinate. Since the shell represented by the left-hand figure is 

 never tricarinate, and it has also been well described and figured by 

 M'Coy, in the 'Brit. Pal. Poss.' 1855, p. 532, pi. 3 h. figs. 11 and 12, 

 it would, I think, be convenient to take the other shell which is 

 tricarinate, and which bas not been elsewhere described, as the type of 

 M. angulata. I bave examined all the Carboniferous Gasteropoda in 

 the Natural History Museum and in the Oxford Museum, and have 

 also made numerous inquiries, but have not been able to obtain any 

 more information concerning this species, neither do I know of an3 T 

 other tricarinate shell bearing a greater resemblance to Phillips's 

 figure. 



Many different shells have been referred by succeeding palaeonto- 

 logists to this species, which are not identical with either of the 

 shells. J. E. Portlock * has erroneously identified a shell as M. 

 angulata, but it differs from both of Phillips's figures by its greater 

 spiral angle, the form of the band, and its ornamentation. A. 

 Sedgwick and P. M'Coy f mention a shell which seems to me dis- 

 tinct, but it is so much imbedded in the matrix that it is difficult to 

 make anything of it. The shell referred to as M. angulata in the 

 ' Cat. of W T est. Scot. Poss.' p. 56, is of much smaller proportions, 

 and is differently ornamented. A. d'Archiac and E. de VerneuilJ 



* Geol. Rep. Londonderry, p. 418, pi. xxxi. fig. 5. 

 t Brit. Pal. Bocks, p. 531. 



\ Trans. Geol. Soc. 2nd ser. vol. vi. p. 356, pi. xxxii. figs. G, 7. 



