ORDER PECTINIBRANCHIATA. 79 
furrowed. The animal of several species resembles that of 
the Olive, the foot being still more developed. (Ancillaria 
cinnamomea, Lam., &c.) 
Douium, Lam. 
Those in which projecting ribs that follow the direction of 
the whorls render the margin undulated ; the inferior whorl is 
ample and swollen. Montfort subdivides them into 
Do.LiuM, properly so called, when the lower part of the 
columella is twisted. (Buc. olearium, List., &c.) And 
PERDIX, when it is trenchant. (Bucc. Perdix, List.) 
Their animal has a very large foot widened before, a pro- 
boscis larger than its shell, and slender tentacula, on the 
external side of which, and near the base, are the eyes; the 
head has no veil, nor has the foot an operculum. 
HARPA, Lam. 
The harpe are easily recognized by the projecting trans- 
verse ribs on the whorls, the last of which forms a lip on the 
margin. The shell is beautiful, and the animal has a very 
large foot, pointed behind, and widened in its anterior portion, 
which is distinguished by two deep emarginations. ‘The eyes 
are on the sides of the tentacula, and near their base. It has 
neither veil nor operculum. Buccinum harpa, L., and the 
other species long confounded with it, &c. Messrs. Reynaud, 
Quoy, and Gaymard have observed, that, under certain cir- 
cumstances, the posterior part of the foot is spontaneously 
detached. 
PURPURA, Brug., 
Is known by its flattened columella, which is trenchant near 
the end opposite to the spire, and which, with the external 
margin, forms a canal there, sunk in the shell, but not salient. 
The purpure were scattered among the buccina and the 
