326 MISS DONALD ON PROTEROZOIC GASTEROPODA [| May 1902, 
CyrtostropHa TorauaTa (M‘Coy). (Pl. VIII, figs. 1, 1 a, & 18.) 
Murchisonia torquata, F. M‘Coy, 1852, ‘ Brit. Palzoz. Foss.’,p. 294 & pl. xiv, 
figs. 19, 19a; J. Morris, 1854, ‘ Catal. Brit. Foss.’ 2nd ed. p. 259; J. Sowerby, 1867, 
‘Siluria’ 4th ed. p. 533; J. J. Bigsby, 1868, ‘Thes. Silur.’ p. 159; J. W. Salter, 
1873, ‘Catal. Cambr. Foss.’ p. 185, non p. 191; A. C. Ramsay, 1881, Mem. Geol. 
Surv. vol. iii, ‘Geol. N. Wales’ 2nd ed. p. 468; R. Etheridge, 1888, ‘ Foss. Brit. Is.’ - 
vol. i (Paleozoic) p.114; H. Woods, 1891, ‘ Catal. Type Foss. Woodward. Mus.’ p. 108. 
Diagnosis.—Shell conical, composed of about eight whorls. 
Whorls increasing at a moderate rate, convex, with a swelling or 
thickening of the upper edge immediately below the suture. Band 
situated near the middle of the body-whorl and considerably below 
on the earlier whorls, slightly grooved, and bounded by a raised thread 
on each side. Lines of growth sharp, stronger above than below, 
curving back to the band above and rather more obliquely forward 
below, and forming crescents on the band itself. Aperture sub-ovoid, 
Remarks and Resemblances.—This species is at present 
known only in the form of external moulds, which are more or less 
weathered and imperfect. The band and aperture are not very 
well preserved in any of the specimens. Salter, in his ‘Catalogue of 
the Cambrian & Silurian Fossils’ p. 191, refers Murchisonia tor- 
quata to Hormotoma. Though greatly resembling members of that 
genus inits convex whorls, it differs decidedly in having less oblique 
lines of growth. It is most like some of the species of Cyrtostropha, 
and I refer it to that subgenus for the present, because although the 
spiral lines with which the members are generally ornamented are 
not visible, there appear to be traces of a groove above the band on 
‘one or two specimens. ‘Thisis a very characteristic feature in Cyrto- 
stropha, in conjunction with the convex whorls and grooved band. 
Dimensions.—the largest example that I have seen is in the 
Woodwardian Museum, Cambridge, from the Kirkby-Moor Flags of 
Spital. It is very badly preserved, the apex is absent, and only six 
whorls remain: these measure 18 millimetres in length and 7 mm. 
in width. Next to it, in the same piece of rock, is the specimen 
which was probably M‘Coy’s type: it consists of about eight whorls, 
measuring 11 mm. in length and 6 mm. in width. Fragments 
of other specimens from both Spital and Benson Knott show the 
surface better. ‘Two of the examples figured (Pl. VITI, figs. 1 & 1 a) 
are in the Rev. M.S. Donald’s collection; fig. 1 measures 13 milli- 
metres in length and 5 mm. in width. 
Localities and Horizon.—M ‘Coy states that this species is 
common in the Upper Ludlow of Spital and Benson Knott, Kendal ; 
also in the tilestones of Storm Hill, Llandeilo (Caermarthenshire), 
There are specimens from all these localities in the Woodwardian 
Museum, Cambridge. Salter (op. cit. p. 191) also refers an ex- 
ternal mould from Pontaryllechau to this species; but both it and 
that from Storm Hill are too poorly preserved to be referred to 
C. torquata with certainty, there being no trace of band or surface- 
ornamentation. Some external moulds, also from Kendal, are in the 
Carlisle Museum. The Rev. M.S. Donald has about six specimens 
in his collection, from the Kirkby-Moor Flags, Lily Mere. 
