Semicassis pyrum

Taxobox
name = "Semicassis pyrum"


image_caption =
regnum = Animalia
phylum = Mollusca
classis = Gastropoda
ordo = Littorinimorpha
familia = Tonnidae
subfamilia = Cassinae
genus = "Semicassis"
species = "S. pyrum"
binomial = "Semicassis pyrum"
binomial_authority = (Lamarck,1822)

"Semicassis pyrum" is a large gastropod mollusc of the family Cassidae known as a helmet shell. It is found all around New Zealand, and in Australia in New South Wales and southern Australia including Tasmania, in shallow water and down to depths of about 70 m. The shell is moderately large, fairly solid, subglobose, with a weak shoulder angle, bearing rounded nodules. The surface is smooth, except for a few incised spiral lines, both on the shoulder of the early whorls and on the lower base. The outer lip is roundly recurved and smooth, and the inner lip callus shield is wide, and warped outwards medially, where it bridges a moderate umbilicus. Colour is pinkish-buff, with five revolving bands of reddish-brown wavy maculations. The tip of the siphonal canal is violet tinged.

This species is quite variable in shape over its geographic range.

Maximum shell height is 89 mm, and width 60 mm.

References

* Powell A. W. B., William Collins Publishers Ltd, Auckland 1979 ISBN 0-00-216906-1