Siphonal canal always has a brown or black mark within it (1). The protoconch (2), lacking periostracum and obvious sculpture, has a little more than two complete tumid, smooth whorls and is the same size on shells at all growth stages. The parietal lip (3) does not spread onto the body-whorl of juveniles.
Juvenile, H. 3 mm Llŷn, North Wales, March 2016.
Part of adult, H. 10.5 mm, Portland, Dorset, England, April 2012.
: flic.kr/p/2oiGpnC
Sets of OTHER SPECIES:
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