NATICA. 45 



Size. — Two specimens measure respectively 14 mm. high by 12 mm, wide, and 

 18 mm. high by 16 mm. wide. 



Localities. — In the Barnstaple Athenaeum are two casts and one mould from 

 Sloly, and in the Museum of Practical Geology, seven casts from the Marvvood 

 beds, and four from " Pilton beds, Croyde Bay," besides another poor specimen 

 from Grojde, which appears to have come from a higher horizon. A minute cast 

 (fig. 13) from the Cucullsea beds of Baggy Point, in Mr. Hamling's Collection, 

 which has a very low spire, seems to be the young form of this species. 



Remarks. — These fossils have been variously referred to Natica meriddonalis, 

 Macrocheilus imbricatum, and Pleurotomaria, but they certainly have nothing to do 

 with either. With two exceptions they have a red ferruginous matrix, indicating 

 that they came from the top of the Sloly beds. The surface is seen from the mould 

 to be distinctly smooth. The shape of the mouth is well shown in some specimens, 

 the outer lip curving regularly to the front, until it meets the inner lip, where it 

 curls round, forming the free margin of a long oblique cylinder of shell, which is a 

 kind of spurious columella. The height of the spire is rather variable, and 

 probably increases with age. This species is named after Townshend M. Hall, 

 Esq., F.G.S., who made the Collection now in the Barnstaple Athenseum. 



Affinities. — It is easily distinguished from N. meridionalis, Phillips,^ by its 

 smoothness, and its greater size and shortness. 



Natica striolata, F. A. Romer,*^ diflPers in being finely striated, and in having a 

 rather higher spire. 



Natica purpura, F. A. Romer,* is much more elongate, and has a much higher 

 spire. 



Naticopsis elegantida, (Ehlert and Davoust* (which appears to agree generically), 

 is very similar to the young form of our shell, but seems distinguished by having 

 transverse and also fine longitudinal strias. 



2. Genus — Natica, Adanson, 1757. 

 1. Natica? meridionalis, Phillips. Plate V, fig. 14. 



1841. Natica meridionalis, Phillips. Pal. Foss., pi. xxxvi, fig. 173. 



Description. — " Shell small, with equidistant undulations, which are most 

 prominent on the upper part of the whorl, and pass thence in a directly longitudinal 

 direction " (Phillips). 



1 18il, Phillips, ' Pal. Foss.,' p. 94, pi. xxxvi, fig. 173. 



2 1850, F. A. Eomer, ' Beitr. Harz.,' pt. 1, p. 33, pi. v, fig. 7. 



3 Ibid., pt. 1, p. 34, pi. V, fig. 8. 



* 1880, (Ehlert and Davoust, ' Bull. Soc. Geol. Fr.,' ser. 3, vol. vii, p. 712, pi. xv, figs. 3— 3 c. 



