498 Ww. J. SOLLAS ON THE SILURIAN DISIRICT 
6. HoLoPELLA GRACILIS, sp. nov. (Pl. XXIV. fig. 5.) 
Shell slender ; apical angle 20°; whorls smooth, very slightly con- 
cave, number ? (five are shown); sutural angle 70°. 
Remarks. This species appears to be intermediate between H. 
gracilior and H. obsoleta ; its spire is less slender than that of the 
former, and more slender than that of the latter species, while its 
whorls are more convex than in H. gracilior and less so than in 
HT, obsoleta. 
7. HoLopELLA HYDROPICA, sp. nov. (PI. XXIV. fig. 4.) 
Shell slender ; apical angle (?); whorls smooth, bulging below, 
contracted above ; sutures plain, very slightly imbricating ; sutural 
angle 85°. 
Remarks. The form of the whorls of this shell is very characteristic, 
and much resembles that of the Carboniferous Loxonema impendens, 
M‘Coy. 
8. HoLopELLA MINUTA, sp. nov. (Pl. XXIV. fig. 6.) 
Shell slender; apical angle 22°; whorls smooth, number ? (nine 
exposed, including globular apical point), twice as wide as high, 
convex ; Spats es deep, simple. 
Tenet 353 breadth of lowest whorl 7,”. 
Remarks, This species is distinguished from H. gregaria by its 
wider and squatter whorls, and from //. monile by the same charac- 
ter, as well as by its larger apical angle. 
9. CycLONEMA ANGULATUM, sp. nov. (Pl. XXIV. fig. 15.) 
Shell conical; apical angle 65°; whorls four in number, angu- 
lated spirally ; on body-whorl 4 angulations at equal distances of 
z,' apart, the highest one 51,” below the suture; in the preceding 
whorl three angulations—one immediately above the lower suture, 
another in the middle, and the third midway between the median 
angulation and the upper suture. Surface obliquely striated, strize 
very fine and close, crossing the angulations and maintaining the 
same direction from front to back without inflection completely 
across each whorl. 
Remarks. This shell is didanre fete from allied species by the 
fact that the angulations are not plain along their summit, but 
crossed by the transverse strive. 
10. CycLoNEMA SIMPLEX, sp. noy. (Pl. XXIV. figs. 10, 10 a.) 
Shell obtusely conical; apical angle 85°; whorls three or four in 
number, body-whorl large; mouth not visible, but apparently ellip- 
tical in shape with the long pee vertical ; surface ornamented with 
revolving thread-like ridges =}y " apart, with an occasional secondary 
ridge interposed, and. a, strizee of exceeding fineness, only 
visible in a good light. 
Remarks, ‘This species is exceedingly similar to Turbo crebristria, 
M‘Coy, from the Bala Sandstone of Milford, Montgomeryshire. 
