Vol. 58.] REFERRED TO MURCHISONIA AND PLEUROTOMARIA, 325 
CyrrtostropHa Broincta (M‘Coy). (PI. VII, figs. 9, 9a, & 10.) 
Murchisonia bicincta, ¥. M‘Coy, 1846, ‘Syn. Silur. Foss. Irel.’ p. 16 & pl. i, fig. 17 ; 
J. Morris, 1854, ‘Catal. Brit. Foss.’ 2nd ed. p. 258; J. Sowerby, 1867, ‘ Siluria,’ 
4th ed. p. 532; J. J. Bigsby, 1868, ‘ Thes. Silur.’ p. 157; (?) J. Armstrong, J. Young, 
& D. Robertson, 1876, ‘Catal. West. Scot. Foss.’ p. 19; A. C. Ramsay, 1881, Mem. 
Geol. Surv. vol. iii, ‘Geol. N. Wales’ 2nd ed. p. 414; R. Etheridge, 1888, ‘Foss. Brit. 
Is.’ vol. i (Paleozoic) p. 113; (?) J. Horne & B. N. Peach, 1899, Mem. Geol. Surv. 
*Silur. Rocks of Britain’ vol. 1, pp. 682, 695 & 699; non J. Hall, 1847, ‘Pal. N. Y.’ 
vol. i, p. 177 & pl. xxxviii, fig. 5. 
Diagnosis.—Shell small, conical, composed of about ten whorls. 
Whorls slightly convex, increasing gradually. Band situated on 
the widest part of the whorl, low down and but a short distance 
above the suture, almost level with the surface, being but slightly 
grooved, bounded on each side by a strong raised thread. There is 
a slight groove above the band, limited by a faint thread, and indi- 
cations of two other threads are perceptible immediately below the 
suture. Lines of growth not preserved. Aperture unknown. 
Remarks and Resemblances.—The Museum of Science & 
Art, Dublin, contains but one specimen of this species, which is 
M’Coy’s type (Pl. VII, fig. 9). As neither aperture nor lines of 
growth are preserved, its exact relationship cannot be ascertained. 
It bears considerable resemblance to C. scitula and C. corallii, 
therefore I refer it to Cyrtostropha. It is distinguished from both 
these species by its much smaller size, less prominent whorls, and 
the lower position of the band. Although it is entered in the list of 
Western Scottish fossils, I have not seen any shell identical with 
this in the Scottish collections. This species must not be con- 
founded with Murchisonia bicincta, Hall, which is quite distinct, and 
has since been referred to Lophospira by Whitfield,’ being con- 
sidered by him as one of the types of that genus. 
Dimensions.—tThe length=6-25 millimetres, and the width= 
about 3 mm. 
In the Museum of Practical Geology, Jermyn Street, are three 
specimens which agree exactly with C. becencta (M‘Coy) in form and 
ornamentation, except that they are reversed. The varietal name 
perversa is inscribed on the tablet, but I have been unable to obtain 
any clue as to its origin. It has evidently been written there since 
the publication of the Catalogue in 1878, as it is not included 
therein. ' These shells are slightly larger than the type, and all are 
imperfect, none showing either apex or base. Two consist of seven 
whorls: the larger measures 83 millimetres in length; the other, 
which is figured in Pl. VII, fig. 10, measures 8 mm. in length. 
The smallest specimen has only four and a half whorls in a length 
of 5 millimetres. 
Horizon and Locality.—The type, as well as these reversed 
specimens, occurs in limestone of Bala age, Chair of Kildare. 
‘ 
1 Bull, Amer. Mus. Nat. Hist. vol. i (1886) p. 312. 
. Z 
