GASTEROPODA. | LOWER PALASOZOIC MOLLUSCA. 303 
Genus. HOLOPELLA (A/°Coy). 
Etym. édos, entire, ém, an aperture. 
Gen. Char.—Shell spiral, elongate, slender, of numerous gradually increasing whorls, generally crossed by 
slightly arched strie ; mouth circular, with the peritreme entire; base rounded, with or without a minute 
umbilicus. 
Those shells have hitherto been confounded with the recent genus Twrritella, from which they differ com- 
pletely in the entire peritreme and definite round margin to the mouth, thus approaching much nearer to 
Scalaria. From Chemmitzia they differ in the smaller size of the body whorl, and in neither it nor the mouth 
being produced anteally. 
HoOLOPELLA CANCELLATA (Sow. Sp.) 
Ref. = Turritella Id. Sil. Syst. t. 20. f. 18. 
Sp. Ch_—Acutely conic, whorls gently convex, with about five delicate, spiral threads, crossed by very fine 
close strize of growth. Width about three lines. 
Only one imperfect fragment has occurred to us of this species, which is however easily recognized by the 
spiral threads cancellating the transverse strize. 
Position and Locality —Upper Ludlow quartzites of Lambrig Fell, Kendal, Westmoreland. 
HOLOPELLA conica (Sow. Sp.) 
Ref. = Turritella conica Sow. Sil. Syst. t. 3. f. 7a and 8. 
Sp. Ch.—Ovate, pointed, apical angle 40°; whorls six, most convex below the middle, crossed by fine, 
slightly arched striz, strongest at the suture. Length three lines, proportional width =, length of last 
whorl =. 
Position and Locality —Rather rare in the tilestone of Storm Hill, Llandeilo, Caermarthenshire. 
HoLopELLA GRAcILIOR (/*Coy). Pl. 1. K. fig. 33. 
Ref—tld. M°Coy, Ann. Nat. Hist. 2nd Series, Vol. VII. p. 47. 
Sp. Ch.—Very slender, spiral angle 15°; whorls smooth (number unknown), slightly and evenly convex, 
suture deep, simple, sutural angle 95°; width at base five lines, length of last whorl three lines. 
This is distinguished from the H. obsoleta by its more slender spire (as indicated by the difference in their 
spiral angles, less convex whorls, &c.) 
Position and Locality —Schists of Dinas Bran, Llangollen, Denbighshire. 
Explanation of Figure—PI\. 1. K. fig. 33, natural size. 
HoLOPELLA GREGARIA (Sow. Sp.) 
Ref. = Turritella gregaria Sow. Sil. Syst. t. 3. f. 1 f. 
Sp. Ch.—Acutely conic, apical angle 25°; spire of about six whorls (four usually preserved), each ob- 
securely angulated in the middle; shell thick, surface with sharp, rather distant transverse scaly lines of 
growth. Length five lines, proportional width =>, length of last whorl ;;. 
This has much the shape of the Murchisonia torquata (M°Coy), but has neither the band nor the collar 
to the sutures; its smaller size, more rapidly tapering form, and subangulated whorls, separate even casts 
easily from the H. obsoleta (Sow. sp.) It usually occurs as smooth casts, the scaly line of growth adhering 
to the matrix. 
Position and Locality—Common in the Upper Ludlow limestone of Beckfoot, Kirkby Lonsdale, West- 
moreland; in the tilestone (Upper Ludlow) of Horeb Chapel, Llandovery, S. Wales; sandy schists of Plas 
Madoe, N. of Llanrwst; Upper Ludlow rock of Underbarrow, Kendal, Westmoreland. 
