The shapes of the whorls in the topmost portion of the shells of P. canaliculata
were also observed and described using outlines assigned in the sutures. Outline
coefficients (N = 199) were calculated and interpreted using multivariate Principal
Component Analysis (PCA). Fig. (4) illustrates the mean shell shape (top/whorl
portion) of P. canaliculata (a) female and (b) male. The first and second principal
components (PC1 and PC2) provided a good summary of the variation for the
top/whorl portion of the shell. PC1 and PC2 for both the female and male top/whorl
portion of the shell accounted for more than 85% and 88% of the total variance
respectively, as presented in