Alaginella ochracea (Angas, 1871)
Diagnosis: Shell small, transparent colourless to fawn or white, strongly narrowed anteriorly; spire medium in height; aperture moderately wide; lip strongly thickened internally, smooth or denticulate, slightly flared posteriorly; external varix present; posterior notch weak; columella with four strong plaits, rectangular in cross section, occupying slightly more than half the aperture.
Size: Adults 3 – 4 mm in length
Museum Collection: Port Stephens, NSW, to
Comparison: A. ochracea and A. gatliffi are very similar, but A. gatliffi is found below about 120 metres and A. ochracea occurs intertidaly and down to about 60 metres, and is common as a beach shell. A. ochracea is relatively narrow, A. gatliffi is wider. Both species have four strong plaits on the columella; in A. ochracea the third and fourth plaits are solid and rectangular in cross section, but in M. gatliffi they are sharp and thin (See Identification of beach specimens).
Synonymy: Laseron introduced the name Marginella ochracea crescere Laseron, 1948 for a specimen which he described as being “broader with a more pronounced shoulder” (Hewish in Wilson, 1994).
Remarks: Willan (pers. com.) reported collecting numerous live specimens by washing a sample of the bryozoan Scuticella sp. from 16 metres off Cape Byron, NSW.
Fig. 1: North Harbour, Port Jackson, intertidal under stones (C.313044). This is the specimen figured by Laseron (1948, fig. 33).
Fig. 2: SYNTYPE of Marginella ochracea crescere Laseron, 1948; off Point Halliday, NSW, in 9-10 fathoms (16-18 m) (C.103368)
Copyright Des Beechey 2003