RHAPHISTOMA. 55 



from the west of Saunton Court in the Woodwardian Museum ; one from Ironport 

 in my Collection ; and one from Kingdon's, Sliirwell, in the Barnstaple Athenaeum. 



BemarJis. — This little species so exactly agrees with the Carboniferous shell 

 from Belgium, Scotland, and the Isle of Man, described by de Koninck as lihapliis- 

 toma Junius, that there can be no doubt of their identity. The agreement extends 

 both to shape and markings, umbilicus and umbilical keel. Almost the only 

 difference is that our shells are decidedly smaller, and that de Koninck does not 

 notice the downward continuation of the sutural corona, which is very obscurely 

 observable in one only of our specimens. De Koninck also mentions a depres- 

 sion like a sinus-band, which, however, he regards, not as a true sinus-band, but 

 as a band similar to that seen in some forms of Euomphalus, in the neighbourhood 

 of which he therefore places the genus. In our shells this character cannot be 

 distinctly observed. 



This species seems to bear very much likeness to the Pleurotomaria expansa, 

 Phillips, of the ' Pal. Foss.,' and it is most probable that Phillips's figure represents 

 a specimen of it. That specimen I have not been able to find. In its figure 

 there are indications of a ribbed sinus-band, which certainly does not exist in our 

 present species. On comparing, however, this figure with his description (which 

 is quoted from the description of PI. ewpansa in the ' Geol. Yorks.') it seems most 

 likely that this appearance in the figure was due to a confusion with the adjoining 

 matrix. At all events, it is pretty clear that the shell he described from Devonshire 

 is quite distinct from the true PL expansa, Phillips, of Yorkshire, which is clearly 

 a Pleurotomaria, is both spirally and obliquely striated, and has no signs of any 

 sutural crown. 



Whether PI. gracilis, Phillips, is more than a variety of this species is question- 

 able. Our specimens seem intermediate between Phillips's figures of his two 

 species, but I have been unable to find the types of either, and the data given by 

 him are too meagre for a satisfactory conclusion. If, however, the species which I 

 have described from Lummaton is really identical with Phillips's PI. gracilis, then 

 that shell is certainly distinct from the present, and differs from it by having a 

 more distinct and elevated sinus-band. 



Affinities. — Natica discus, F. A. Romer,^ is very similar in shape, but is micro- 

 scopically striated. It perhaps belongs to the same genus, but is so much larger 

 that it is probably a distinct species. 



Trochus oxygonus, F. A. Romer,^ has a much sharper basal angle, and perhaps a 

 slightly lower spire. 



The flat variety of Pleurotomaria crenatostriata, Sandberger,^ is very similar, 



1 1852, F. A. Eomer, * Beitr. Harzgeb.,' pt. 2, p. 88, pi. xiii, figs. 11 a, b, c. 



2 1813, P. A. Homer, ' Verst. Harzgeb.,' p. 29, pi. viii, fig. 5. 



^ 1853, Sandberger, 'Verst. Rlieiu. Nassau,' p. 188, pi. xxiii, figs. 2 — 2 d. 



