INVoLUTE. | 
Genus 11.—Fissuretia.— Bruguiére. 
Shell subconic, oblong, shield-shaped, or conically depressed, 
concave within, destitute of spiral convolutions, with the vertex 
perforated, and directed towards the front of the shell; perfo- 
ration subovate, elongated, or nearly round in some species; 
margin thickened around the inside, and generally crenulated ; 
muscular impression visible near the inner edge, all round, 
widest on the sides next the anterior end; outer surface 
striated, ribbed, grooved, or radiated from the vertex to the 
margin, and generally decussated by lines of growth, or con- 
centric ribs. 
1. Fissuretta Grzca, pl. XII, f. 10, 11. 
Fissurella Greca, First Ed., pl. 36, f. 10, 11; Fleming, p 
364; Ib., Ency., p. 66; Brown, Popular Ency., II, p. 378, pl. 
17, f.96; Patella Greca, Linné, Syst., p. 1262; Brown, Ency., 
p- 467; Ib., Wernerian Mem., p. 533; Turton, Brit. Fau., p. 
198; Martini, I, pl. 11, f.98; Pennant, IV, p. 144, pl. 89, f. 
153; Montagu, p. 492; Maton and Rackett, p. 236; Patella 
reticulata, Donovan, I, pl. 21, f. 3. 
Shell oblong-oval, subdepressed, thick, of a dull brownish- 
yellow colour, with numerous, strong, longitudinal ribs, radiating 
from the vertex to the base, some of which are thicker than the 
rest, and in some instances tuberculated by the crossing of the 
finer, concentric, thread-like stria, which cover the whole sur- 
face, the interstices presenting a punctated appearance; vertex 
perforated with an oblong-ovate fissure; inside smooth, white, 
sometimes of a dull, pale brownish-purple; margin not flat, but 
somewhat indented, or arcuated at the side, and finely crenu- 
lated on the extreme edge. Length three-quarters of an inch; 
breadth about half an inch; height a quarter. 
The above are the general dimensions of the species, but is 
met with in deep water of a larger size, off the Devonshire 
coast, as well as that of the Isle of Man; in which locality 
Professor Forbes dredged some very large specimens, mea- 
suring upwards of an inch in length, and more than five-eighths 
in breadth. 
It inhabits most of the British coasts, but is never plentiful ; 
the Dorset, Kentish, Devonshire, and Northumberland coasts 
may be noticed; the Frith of Forth, the Frith of Clyde, and 
Argyleshire coasts, in Scotland; and Lough Strangford, Port- 
marnock, and Dublin Bay, Ireland. 
Genus 12.—Si1pHo.—Brown. 
Shell ovate, subconic; vertex reflected, and slightly spiral ; 
with a small dorsal fissure situate near the vertex, terminating 
internally by a rhombic, funnel-shaped syphon, or cup, in some 
species, but devoid of it in others; base ovate; exterior surface 
ribbed, or striated. 
Section I—Cavity provided with a funnel, leading from 
the fissure. 
1. SrpHo Noacurna, pl. XII, f. 14, 15, 16. 
Sipho striata, First Ed., pl. 36, f. 14, 15, 16; Brown, Conch. 
Text Book, p. 100, pl. 14, f. 21; Ib., Popular Ency., II, p. 378, 
pl. 17, £113; Fisswrella Noachina, Smith, Wernerian Mem., 
VIII, p. 43; Sowerby; Cemoria Flemingii, Leach. 
Q 
MOLLUSCA. 61 
Shell brownish-white, very strong, ovate, subconic; vertex 
slightly spiral, and inclining anteriorly; with a small triangular 
fissure behind, broad below and acute above, situate near the 
vertex; aperture white, smooth, and slightly crenulated on the 
margin. 
First discovered as British, by my friend Stewart Ker, Esq., 
at Greenock, where dead shells are not uncommon. Two spe- 
cimens were dredged alive, off Rothesay, by my friend James 
Smith, Esq., of Jordan Hill, near Glasgow, while I accompanied 
him on a dredging excursion, in his yacht, in 1837. 
It seems to have been very plentiful in the Clyde at one 
period, as it occurs abundantly in a subfossil state in the ele- 
vated marine bed of the Clyde, at Dalmuir. 
Section II._—Destitute of an internal funnel. 
2. Srpno raprata, pl. XII, f. 20. 
Sipho radiata, First Ed., pl. 36, f. 20; Fissurella apertura, 
Fleming, p. 364; Patella apertura, Montagu, p- 491, pl. 13, f. 
20; Fleming, Ency., p. 66; Patella Noachina, Brown, Ency. 
Brit., p. 467; Maton and Rackett, p. 236; the young of Fis- 
surella Greca, Forbes, Mal. Mon., p. 34. 
“ With a subconic, subpellucid, white shell, marked with 
strong, longitudinal, tuberculated ribs, and a few circular ridges, 
that give it a cancellated appearance; vertex reflected, the point 
very small, and turning downwards; not detached, but adhering 
to the top of the shell, sometimes making one conyolution ; 
immediately above which is a rhomboid perforation. Inside 
smooth, glossy, white ; margin oval, edge crenated by the ribs. 
Length not quite a quarter of an inch, scarce an eighth of an 
inch in height. In one instance this shell had a few brown 
streaks running half way up the margin.”—Montagu. 
In my Paper in the Encyclopedia Britannica, I considered 
this the Patella Noachina of Chemnitz; but on seeing the 
original shell in the British Museum, I perceived that it was a 
different species from Sipho Noachina. It is more elliptical 
than the latter shell, the longitudinal ribs larger, set more apart, 
and the concentric stri# not so well marked; but a stronger 
character than these is the form of the foramen, which is nearly 
lance-shaped in §. Noachina, with an internal funnel, whereas 
it is oblong-ovate in S. radiata, and destitute of an 
funnel; with which character, a specimen found in 
Tenby, by General Bingham, expressly agreed. 
internal 
sand at 
In 1819, when I made my drawing from Montagu’s original 
specimen in the British Museum, my friend Dr. Leach con- 
curred in opinion, that specimens with which I presented him, 
from the Clyde, were perfectly distinct from that in the 
Museum, as did also Mr. J. E. Gray; and the Doctor agreed 
in the propriety of instituting a new genus for their reception ; 
but it appears he afterwards thought Cemoria a better name 
than that which I had previously chosen. 
Found at Falmouth Harbour, Cornwall, and in Saleomb Bay, 
Devonshire, by Colonel Montagu; at Tenby, Wales, by General 
Bingham; and in Zetland, by Dr. Fleming; and Professor 
Forbes dredged it plentifully off the Manx coast, but considered 
it the young of Fisswrella Greca, with which opinion I do not 
agree. It is not half the size of 8. Noachina. 
