FAMILY PURPURIDEZ — PURPURA. 135 
GENUS PURPURA. Adanson. 
Animal with a large head. Trunk short or obsolete. Tentacles two, generally in front and 
approximated, conical, and with the eyes on an inflated portion near the middle, and 
external. Mouth beneath, almost always concealed by the foot. Foot moderately large, 
advanced and bilobed in front. Mantle forming a distinct siphon in front. Gills in two 
unequal series. Orifice of the oviduct at the entrance of the branchial cavity ; that of the 
vas deferens on the right side of the neck, at the end of the male organ, which is generally 
voluminous. Vent on the same side. Marine. Shell, ovate, thick, smooth, tubular or 
angular: spire short; aperture dilated, emarginate at the base, having a subcanaliculate 
oblique sus. Columella depressed, ending in a.point. 
PurpPuRA LAPILLUS. 
PLATE VIII. FIG. 175. 
(STATE COLLECTION.) 
Buccinum lapillus. Lrx, Gmel. Syst. Nat. 1202. Lam. An. sans vert. Ed. prior, Vol. 7, p. 244. 
Purpura id. Russex, Ess. Journ. Nat. Hist. Vol.1, p. 69. 
2h id. Apams, Bost. Journ. Nat. Hist. Vol. 2, p. 268, 
‘Ps id. GouLp, Invertebrata of Mass. p. 301. 
Description. Shell ovate, thick and solid: spire short and very acute ; suture impressed. 
Whorls five, with deep revolving furrows and intervening ribs, giving frequently a strong 
carination to the whorls, which have moreover numerous slight transverse wrinkles. Aperture 
ovate: lip arched and subacute, with obscure revolving ridges within the margin. Pillar-lip 
produced, concave externally at the base ; canal short. Opercle horny, oval. 
Color. Varying from white to lemon and orange yellow ; aperture reddish brown within. 
Length, 0°6 - 0:8. 
This shell occurs along our coast, from Cape Cod to Florida. It is usually described as 
varying very much in its markings, constituting strongly marked varieties, which have been 
considered by others as distinct species. Among these are the two following. 
