182 MOLLUSCA. 
Axis one inch; diameter seven-tenths of an inch. 
May well be compared with the coarse, solid, sulcated variety of 
Lattorina angulifera. 
Figure 206, front view of the shell; 206 a@, base of the shell; 206 6, 
sculpture, enlarged. 
Trocuus aTER (Lesson), Voy. de la Coquille, Moll., pl. 16, f. 2. 
Puiviprr, Abbild. 1., 188, pl. 5, f. 6. 
AnimaL dusky-brown above: foot rounded oblong, with a median 
longitudinal furrow, slightly notched in front, bright ochre-colour. 
Head large and distinct, prolonged into a sort of muzzle, very dark 
brown above, ochreous beneath, around the mouth. ‘Tentacles very 
long and slender, slaty above, yellowish beneath, and finely annulated 
with black. Eye pedicles one-fourth the length of the tentacles, 
divided from them quite to the base; lateral veil, a narrow, undulating 
fringe, bearing on each side four equidistant cirrhi. Mantle light 
ochreous. Operculum thin, horny, light brown, fading to horn-colour 
when dried. 
It inhabits the crevices of rocks washed by the surf, at Valparaiso ; 
a smaller variety is found at Callao. It is very active in its movements. 
[Reb-aCell 
Figure 211, shell, with the animal, as in motion. 
Trocuus Araucanus (D’Orbigny), Amer. Merid., pl. 55, f. 5-8. 
Anima glossy black above, cream-coloured beneath: mantle ochre- 
ous: tentacles obscurely annulated with black: ocular pedicles large, 
and free one-third the distance to the base of the tentacles; lateral 
membrane furnished with four moderately long filaments on each 
side, the two anterior ones more widely separated than the others and 
longer. Foot remarkable for a slight posterior emargination, which 
frequently presents a bilobed appearance in crawling. When in 
motion the foot is often narrowed and protruded far in front of the 
shell, till it resembles the animal of Voluta. 
