MORPHOLOGICAL VARIATION IN THE PAINTED TOPSHELL, CALL1OSTOMA ZIZYPHINUM (L.) (PROSOBRANCHIA: TROCHIDAE), FROM INTER-TIDAL RAPIDS ON THE IRISH COAST

Shell shape variation in Calliostoma zizyphinum (L.) is examinedwith different techniques of analysis (profile, discriminant,canonical variate and ratio analysis). Shells are collectedfrom five tidal rapids systems, all in very sheltered inlets,where C. zizyphinum is to be found at shore levels higher thanthe normal shore distribution of LWNT to the sublittoral. Shellmorphology varies consistently with the local habitat conditions,such as water flow rate, relative exposure and shore level.populations can be distinguished using various shell parametersand shell profiles. Shells from two different levels in thesame rapids show the effects of their subtly different habitats. (Received 5 February 1987;