GASTEROPODA. 113 



by Mr. Gray, and Mr. S. Wood ; it appears to us very nearly allied to cinulia 

 (=avettana, D'Orb.) in tornatellidce. 



PURPURA (Adans), Lam. Purple. 



Type, P. persica, PL VI., fig. 1. 



Shell striated, imbricated or tuberculated ; spire short ; aperture large, 

 slightly notched in front ; inner lip much worn and flattened. Operc. 

 lamellar, nucleus external. PL VI., fig. 2. Lingual dentition like murex 

 erinaceus ; teeth transverse, 3 crested ; uncini small, simple. 



Many of the purpurce 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 ; it is very destructive to 

 .mussel-beds (Fleming). 



Distr., 140 sp. W. Indies, Brit., Africa, India, New Zealand, Pacific, 

 Chile, California, Kamschatka. From low-water 25 fathoms. 



Fossil, 30 sp. Miocene . Brit., France, &c. 



Sub-genus. Concholepas, Favan. C: lepas (Gmelin sp.) PL VI., fig. 3. 

 Peru. The only sp. diifers from purpura in the size of its aperture, and 

 smallness of the spire. 



?PURPURINA (Lycett, 1847). D'Orb. 



Shell, ventricose, coronated ; spire, short ; aperture, large, scarcely notched 

 in front. 



Fossil, 9 sp., Bath-oolite. Brit. France. The type, P. rugosa, some- 

 what resembles purpura chocolatum (Duclos), but the genus probably belongs 

 to an extinct group. 



MONOCEROS, Lam. 



Etym., monos, one ; ceras, horn. 



Syn., acanthina, Fischer. Chorus, Gray. 



Type, M. imbricatum. PL VI., fig. 4 (Buc. monoceros, Chemn). 



Shell, like purpura ; with a spiral groove on the whirls, ending in a pro- 

 minent spine on the outer lip. This genus is retained on account of its geo- 

 graphical curiosity ; it consists of sp. of purpura, lagena, turbinella, pseudo- 

 liva, &c. 



Distr., 18 sp. W. coast of America. 



Fossil, tertiary. Chile. 



M. gigantens (chorus) has the canal produced like fusus. M. cingulatum 

 is a turbinella, and several sp. belong more properly to lagena. 



PEDICULARIA, Swainson. 



Type, P. sicula. PL VI., fig. 5 (thyreus, Phil.}. 



Shell very small, limpet-like ; with a large aperture, channelled in front, 

 and a minute, lateral spire. Lingual dentition peculiar ; teeth single, hooked, 

 denticulated ; uncini., 3 ; 1, four-cusped, 2, 3, elongated, three-spined. 



