232 MANUAL OF THE MOLLUSCA. 
? RineiouLa, Deshayes. 
Etymology, diminutive of ringens, from ringo, to grin. 
Type, R. ringens, Pl. V., Fig. 21. 
Shell minute, ventricose, with a small spire; aperture notched, 
rolumella callous, deeply plaited; outer lip thickened and 
foflected. 
Distribution, 7 species? Mediterranean, India, Philippines, 
Gallapagos. 
Fossil, 9 species. Miocene—. Britain, France. Ringicula 
is placed with nassa by Dr. Gray and Mr. 8. Wood; it appears 
to us very nearly allied to cinulia = avellana, D’Orbigny) iv 
tornatellide. 
PurPuRA (Adans.), Lam. Purple. 
Type, P. persica, Pl. VI., Fig. 1. 
Shell striated, imbricated, or tuberculated; spire short; 
aperture large, shghtly notched in front; upper lip much worn 
and flattened. Operculum lamellar, nucleus external. Pl. VL., 
Fig. 2. Lingual dentition like murex erinaceus; teeth trans- 
verse, three crested ; uncini small, simple. 
Many of the purpure produce a fluid which gives a dull 
crimson dye; it may be obtained by pressing on the operculum. 
P. lapillus abounds on the British coast at low water, amongst 
sea-weed; itis very destructive to mussel-beds. (Fleming.) 
Distribution, 140 species. West Indies, Britain, Africa, India, 
New Zealand, Pacific, Chili, California, Kamtschatka. From 
low water—25 fathoms. 
Fessil, 40 species. Tertiary—. Britain, France, &c. 
Concholepas, Fayan. C. lepas (Gmelin species) Pl. VI., Fig. 3. 
Peru. The only species differs from purpura in the size of its 
aperture and smallness of the spire. 
Cuma (Humphrey) P. angulifera, inner lip with a single 
prominent fold. 
? PuRPURINA (Lycett, 1847), D’Orbigny. 
Shell ventricose, coronated; spire short; aperture large, 
scarcely notched in front. 
Fossil, 9 species. Bath-oolite. Britain, France. The type 
P. rugosa, somewhat resembles purpura chocolatum (Duclos), but 
the genus probably belongs to an extinct group. 
RHIZOCHILUS, Stp. 1850. 
Example, R. antipathum. Founded on a species of Purpura? 
