MOLLUSCA. 
19 
Involute.] 
nent than the others ; beneath these is a well-defined suture ; these ridges 
are crossed by numerous very fine, waved, obliquely longitudinal, nearly ob- 
solete striae ; colour livid, reddish citron, or purplish, streaked with longi- 
tudinal broad, waved blotches of pinkish red ; these are more regular and 
distinct on the basal rib of each volution, forming an elegant spiral girdle 
from the base to the apex ; aperture somewhat compressed and angu- 
lated ; inside highly pearlaceous ; base flattish, with concentric ridges, 
crossed by obsolete divergent striae or lines of growth, generally of a 
paler colour than the rest of the shell, and usually destitute of spots ; 
outer lip thin, inner lip a little reflected and thickened, somewhat con- 
cave behind, with a slight notch at its junction with the outer lip. Length 
and breadth usually about an inch, but we found it one inch and three- 
eighths in dimensions, in Dublin Bay and Portmarnock, Ireland. It in- 
habits the coasts of Cornwall, South Devon, and Tenby, Wales; Roth- 
say and Loch Ridan, Scotland. 
Figs. 17 and 18. — A variety presented to us by Dr Leach, who ob- 
tained it from George Lyons, Esq. of Tenby, Wales, where it is not un- 
common. 
Figs. 21 and 22 A beautiful smooth variety, dredged in deep water 
off Sunderland, by Mr Dixon of Bishopwearmouth. In Lady Jardine’s 
Cabinet. 
Figs. 24 and 29. — Another smooth variety, dredged in deep water off 
the county of Down, Ireland. 
9. T. discrepans, pi. XI, f. 20 and 23. — First Ed., pi. 45, f. 20 and 
23; Brown, Wernerian Memoirs, II, p. 501, pi. 24, f. 4, 4. 
Shell conic, with seven rounded volutions, well-defined by a hollow, 
broad, and deep suture, and terminating in a pointed apex ; the whole shell 
covered with somewhat obsolete spiral ridges ; a deep groove emanates 
from the centre of the outer lip, and runs spirally to the apex in the mid- 
dle of the volutions ; aperture subquadrangular ; nacreous within ; cir- 
cumference at the base nearly an inch, heighth seven-eighths. 
This species has much the aspect of Trochus Zizyphinus, but differs 
from it in the deep spiral groove ; it is also shorter in proportion to the 
breadth at the base, and more obtuse at the apex. 
One specimen only of this shell was found at Holywood, in Belfast 
Lough, by Miss Templeton of Belfast, and was in her Cabinet. 
10. T. papillosus, pi. XI, f. 13, 14 First Ed., pi. 45, f. 13, 14; Da 
Costa, p. 38, pi. 3, f. 3 ; Donovan, Brit. Sh., pi. 127 ; Brown, Werne- 
rian Memoirs, II, p. 519; Ib., Ency. Brit., VI, p. 452; Fleming, Brit. 
An., p. 323 ; Trochus tenuis, Montagu, p. 275, pi. 10, f. 3. 
Shell conic, thin, fragile ; with eight slightly inflated volutions, terminat- 
ing in a fine pointed apex, and separated by a very slender suture ; whole 
shell ornamented with numerous regular series of papillose, spiral zones, 
each separated by a groove, in which is placed a raised, central, spiral 
line, crossed by very close and minute longitudinal, nearly obsolete striae; 
the volutions are defined by a larger and more elevated zone of papillae 
at their base, which on the body forms a distinct keel; base somewhat 
tumid, with numerous spiral grooves and ridges, on which latter the pa- 
pillae are less distinct than above ; the whole are crossed by numerous, 
more obvious, divergent striae ; aperture wide, quadrangular, grooved, and 
nacred within; outer lip very thin; columella thick, w'ith an obsolete 
plication near its base, where it is slightly reflected, with a concavity be- 
hind; colour citron, or pinkish-brown, the zones on the base studded 
with rather regular, oblong, or arrow-shaped, reddish-brown spots. 
Length an inch and a quarter ; breadth rather less. Found at Pool and 
Weymouth, Dorsetshire; Cornwall; north coast of Devonshire, from 
whence we obtained the splendid specimens which we have figured, mea- 
suring an inch and a half in length and breadth, found also in Dublin 
Bay, and in deep water off Bray, Ireland. 
11. T. striatus, pi. XI, f. 25, 26 First Ed., pi. 45, f. 25, 26 ; T. ery- 
throleucos. Brown, Ency. Brit., VI, p. 452; Turton’s Linne, V, p. 463; 
Lamarck, VII, p. 30; Trochus striatus, Montagu, p. 278; Fleming, Brit. 
An., p. 323; Trochtis conicus, Donovan, Brit. Sh., pi. 155, f. 1 ; Turton, 
Brit. Fau., p. 177; Trochus parvus. Da Costa, p. 41. 
Shell conic, strong, with six flat volutions, hardly defined by the su- 
ture, and tapering to a fine point, with eight or nine strong spiral stri® 
on each volution, intersected by very minute longitudinal stri®, most con- 
spicuous on the body and base, which is flattened and somewhat con- 
cave with circular ridges ; cinereous, or reddish flesh-coloured, with large 
longitudinal, interrupted, zigzag dull crimson, or purplish-brown clouds ; 
broad in some specimens and narrow in others ; aperture obliquely quad- 
rangular, pearlaceous within, except at the margin of the outer lip, which 
is rather strong for its size ; columella thick, a little reflected above and 
narrower beneath, with a slight concavity behind. Length three-eighths 
of an inch ; breadth nearly the same. 
Found in sand at Falmouth, Cornwall ; Salcomb Bay, Devonshire, and 
Pool, Dorsetshire. It is a rare British shell. 
12. T. exiguus, pi. XI, f. 27, 28.— First Ed., pi. 45, f. 27, 28; Mon- 
tagu, p. 277 ; Turton, Brit. Fauna, p. 177 ; Trochus conidus. Da Costa, 
p. 40, pi. 2, f. 4, 4; Brown, Ency. Brit., VI, p. 452; Donovan, Brit. Sh., 
I, pi. 8, f. 2 ; Lamarck, VII, p. 24; Trochus exaspei'atus. Pennant, Brit. 
Zool., IV, p. 126, No. 105. 
Shell conic, strong, with six flat produced volutions, separated by a 
strong spiral belt at the base of each, and terminating in a fine pointed 
apex, each volution ornamented with four or five well-defined spiral cre- 
nated ridges, which being cut diagonally with strong stri®, give them the 
appearance of twisted cord, with deep intervening grooves, crossed by 
strong oblique stri® ; base slightly rounded, with strong circular ridges, 
striated in the same direction, and crossed by divergent, nearly obsolete 
stri®; aperture obliquely quadrangular, whitish, pearly within; outer lip 
strong ; columella thickened and pearlaceous, with an obsolete tooth-like 
process near its base ; colour various, cinereous, brown, dull purplish- 
brown, sometimes reddish, and spotted with white ; apex almost constant- 
ly of a deep crimson, which frequently extends to the second volution ; 
sometimes the spiral zone at the base of the volutions is ornamented with 
square crimson spots. Length rarely three-eighths of an inch ; breadth a 
quarter of an inch. 
This and the preceding species have not unfrequently been confounded, 
but may at once be distinguished from the T. striatus by its being much 
more produced, in the spiral ridges being crenated, the base being rounded, 
the tip of the spire almost invariably crimson, and the inside of the aper- 
ture very slightly nacred. 
Found on the Sussex and Devonshire coasts, and at Treryn Cove, near 
the Land’s End, Cornwall. Montagu found it on the shore between Wey- 
mouth and Portland. It is a rare and very local British species. 
13. T. crassus, pi. XI, f. 6, 7 — First Ed., pi. 45, f. 6, 7; Montagu, p. 281 ; 
Brown, Ency. Brit., VI, p. 452; Ib., Wernerian Memoirs, II, p. 519; 
Turton, Brit. Fau., p. 177; Fleming, Brit. An., p. 322; Ticrbo lineatus. 
Da Costa, p. 100, pi. 6, f. 7 ; Donovan, Brit. Sh., II, pi. 71. 
Shell subconic, very thick and strong, with five rounded volutions, 
separated by a well-defined suture, apex pointed, but not sharp ; base 
somewhat produced and rounded at its edge ; aperture pearlaceous within ; 
suborbicular, somewhat angulated at the junction of the outer lip and 
pillar, and rounded next the outside ; outer lip acute, its inner margin 
dark purplish brown ; columella smooth, white, or nacred, with a blunt 
tooth-like process below its centre ; and a slight groove behind the co- 
lumella, and in others it is slightly subumbilicate ; outside coarse and 
wrinkled ; colour cinereous, or light fawn, covered with fine, close-set, 
zigzag lines of purplish-brown, and sometimes of a blackish purple ; a 
white semilunar patch covers nearly half of the base. Length an inch, 
breadth somewhat less. 
This species is subject to some variation in shape ; some are more 
conic, and the volutions more rounded and tumid than others. 
Found on the coasts of Cornwall, Devonshire, Hampshire, Caernar- 
vonshire, Wales; Dublin Bay, Killough, and plentiful on the rocks at 
Limerick, Ireland. 
Family II — Scalarides. 
Shell devoid of plaits or folds on the columella; margins of the 
aperture united in a circular form. 
Genus 21. — Delphionoidea Brown. 
Spire depressed, surface smooth, divested of spinous processes ; 
aperture orbicular, or nearly so, and not enveloping the body vo- 
lution. 
Subdivision 1 Volutions De.vtral. 
1. D. Unispirala, pi. VIII, f. 32, 33. — First Ed., pi. 51, f. 32, 33. 
Helix unispiralis ; Montagu, p. 443 ; Maton and Racket, Linn. Trans., 
VIII, p. 201 ; Walker, Minute Shells, f. 27. 
Shell glossy white and opaque, with one volution, umbilicate on both 
sides ; aperture orbicular. Diameter scarcely a line. 
Found at Sandwich, and is very rare. 
