31 
Fasciolaria. — Shell sub-fusiform, base canaliculate, no varices ; two or three very oblique 
plaits on the columella, near the canal. 
Plate XVII. Fig. 7- F. trapezium. (Murex trapezium. — Linn.) 
Fusus. — Shell fusiform or sub-fusiform; base canaliculate; ventricose in the middle or 
at the lower part ; no external varices ; the spire elevated and elongated. Right 
lip without any fissure : columella smooth ; operculum horny. 
Plate XVII. Fig. 8„ F. antiquus. (Murex antiquus. — Linn.) 
Pyrula. — Shell sub-pyriform, channelled at the base, the upper part ventricose; no ex- 
ternal varices ; spire short, sometimes flattened. Columella smooth ; right lip with- 
out any fissure. 
Plate XVII- Fig. 9. P. ficus. (Bulla ficus. — Linn.) 
Division II A constant varix on the right margin, in the whole of the species. 
Struthiolaria. — Shell oval, the spire elevated : aperture oval, sinuous, terminated at 
the base by a very short, straight canal, without any notch. Left lip callous, ex- 
panded; right lip sinuous, with an external varix. 
Plate XVII. Fig. 10. S. nodulosa. (Murex stramineus. — Gmel.) 
Ranella. — Shell oval or oblong, rather depressed; base canaliculate; two rows of vari- 
ces on the exterior: aperture rounded or subovate. Varices straight, or oblique, 
half a whorl distant from each other, and forming a longitudinal row on each side 
of the shell. 
Plate XVII. Fig. 11. R. spinosa. (Murex spinosus. — Dillwyn.) 
Murex. — Shell oval or oblong, channelled at the base, with rough, spined, or tubercu- 
lated varices on the exterior. Three or more varices on each whorl, the lower 
ones uniting obliquely with the upper in a longitudinal row: operculum horny. 
(1) Shells with slender abrupt tails, always longer than the aperture. 
Plate XVII. Fig. 12. M. haustellum. (Idem.— Linn.) 
(2) Tails thick, not abrupt, more or less long. 
(а) Three varices. 
Plate XVII. Fig. 13. M. palmarosse. (Murex ramosus. — Linn.) 
(б) More than three varices. 
Plate XVIII. Fig. 1. M. saxatilis. (Idem. — Linn.) [Mrs. Mawe’s Cabinet.] 
Triton. — Shell oval or oblong, channelled at the base; varices either alternate, or rare, 
or nearly solitary, and never forming a longitudinal row : aperture oblong. An 
operculum. 
Plate XVIII. Fig. 2. T. variegatum. (Murex tritonis. — Linn.) 
