Cystiscus angasi (Crosse, 1870)
Diagnosis: Shell minute or small, colourless transparent to opaque white; spire low; outer lip thickened internally, usually smooth, occasionally weakly denticulate centrally; external varix absent; siphonal notch absent; posterior notch absent; lacking collabral parietal callus ridge; columella multiplicate, with up to 8 plaits/lirae.
Size: Up to 3 mm in length.
Comparison: This species is the most triangular in outline of the family. C. connectans resembles it, but is more elongate. (See Identification of beach specimens)
Synonymy: Synonyms given by Hewish in Wilson (1994) are Volvaria lubrica Petterd, 1884; Marginella shorehami Pritchard & Gatliff, 1899; Marginella simsoni Tate & May, 1900; Marginella ringens May 1919; Marginella erma Cotton 1944; Marginella amphora Laseron, 1948; and possibly Marginella angasi melania Laseron 1948
Remarks: This is by far the most common member of the family in NSW, frequently occurring in beach shell grit. Coleman (1981) reported the species living in colonies around five metres depth on bryozoans.
currently understood, the species has a circum-Australia distribution,
occurring over a depth range from the intertidal to 750 metres.
Specimens sorted as this species in the
Hedley (1915) provided a figure of a specimen
which he compared with the type of Marginella
angasi Crosse in the
(1957) provides a description and figure of the animal.
Fig. 1: Middle Harbour, NSW (C.032422)
Fig. 2: a. Syntype of Marginella amphora Laseron, 1948. Point Haliday, NSW, in 15-18 m (C.103371). b. Syntype of Marginella angasi melania Laseron, 1948. Fairlight, North Harbour, NSW (C.103373)
Fig. 3: Long Reef, Collaroy, NSW (C.305120)
Copyright Des Beechey 2004