GasTERopopa.| LOWER PALAZOZOIC MOLLUSCA. 305 
Position and Locality—Common in the Bala sandstone of Mulock Quarry, Dalquorhan, Ayrshire. 
Explanation of Figures.—P|. 1. L. fig. 17, natural size ; fig. 17a, part of one of the whorls of ditto mag- 
nified to shew the striation. 
Genus. LITORINA (Fer.) 
Gen. Char.—Shell thick, striated, ovate; spire short, pointed, rarely exceeding the body whorl in length ; 
mouth oblique, longitudinally ovate, broadly rounded in front, slightly contracted retrally, indented by the 
preceding whorl ; outer lip thin, inner lip thickened and slightly flattened towards the front, frequently deficient 
in the middle; base rounded, imperforate; operculum corneous, of few spiral turns, summit lateral: (animal 
resembling Scalaria, and wanting the filaments at the foot, of Turbo and Trochus). 
Differs from T'wrbo in less size, not being perlaceous, the corneous operculum, We. and from Phasianella by 
the surface not being polished ; known from Trochus by the tumid base and the mouth being longer than wide ; 
and from Monodonta and its subgenera by there being no teeth on the pillar. All the species are phytivorous, 
feeding on the fuci on rocky coasts, only at, or a little below, low-water mark, in every quarter of the earth at 
the present day, but most abundant in cold regions. They seem to occur in every geological stage, gradually 
increasing in number from the Cambrian to recent period. 
The genus Holopea of Hall is proposed for the Silurian species, but, with every disposition to adopt the 
genus, I do not think it can advantageously be employed till some difference of structure can be detected 
whereby to distinguish the species from the others. 
LiroRINA CORALLIL (Sow. Sp.) 
Ref. = Turbo corallii: Sow. Sil. Syst. t. 5 f. 27. 
Sp. Ch.—Ovate, pointed ; apical angle 65°; spire of five slightly-flattened whorls, marked with fine close 
spiral strize (about seven or eight to each of the latter whorls), two larger than the rest (like a band) on the 
circumference of the body whorl, and close to the suture of the spiral whorls; near the apex only one of the 
spiral threads at the upper suture and two near the lower suture are visible; base flattened, imperforate, with 
close spiral striz, mouth broad ovate, little longer than wide. Length five lines, proportional width *, length 
of body whorl =. 
Mr Sowerby’s figure is rather more pointed, and has the whorls rather more convex than the examples 
I have seen, and the band-like strength of one pair of striz is not noticed. The fine spiral threads are 
crossed by very minute straight lines of growth. Usually found covered by the spheroidal growths of the little 
coral Stenopora fibrosa, shewing that it dwelt, like recent Litorine, in shallow water. 
Position and Locality.—Not uncommon in the Upper Ludlow sandstone of Benson Knot, Kendal, West- 
moreland, 
Lirorina octavia (d’Orb. Sp.) 
Ref. = Turbo carinatus Sow. Sil. Syst. t. 5. f. 28 (not of Min. Con. t. 240, nor Born.) = Turbo octavia 
d@Orb. Prod. Pal. p. 30. 
Sp. Ch.—Ovate, pointed, apical angle 65°, of four very convex whorls; about three equidistant, delicate, 
thread-like, spiral ridges, on each whorl of the spire, to which three or four closer ones are superadded on the 
base of the body whorl, which is convex and imperforate ; whorls crossed by fine, close, slightly oblique lines of 
growth. Length seven lines, proportional width 4, length of body whorl &. 
In Mr Sowerby’s figure above referred to the transverse strice of growth are much too coarse and wide 
apart. Commonly found buried in investing growths of Stenopora fibrosa. 
Position and Locality—Not common in the Upper Ludlow quartzite of High Thorns, Underbarrow, Ken- 
dal, Westmoreland ; Upper Ludlow rock of Woolhope ; Upper Ludlow of Burton and Brockton, near Wenlock. 
[rasc. 11.] Rr 
