T. excavatus.
T. nanus.
T. pyramidatus.
T. erythroleucos.
T. imperialis. The imperial Trochus. Pl. [23], fig. 6.
Species umbilicated, spire very depressed, sharp and radiated at their circumference by the preservation of an angular canal from the middle of the right margin. This species is rare and beautiful, found in New-Zealand.
T. zizyphinus. The livid Trochus.
Species with strong transverse striæ; colour livid, with undulated streaks of red or brownish carnation.
T. agglutinans. The agglutinating or Carrier Trochus.
Species umbilicated, with spire very depressed; the base much enlarged, and as if excavated by the large projection of the angle of the right edge, which advances much beyond the rounded columellar edge; generally covered with shells, stones, or coral.