Fig. 7From: New size data on the enigmatic Spirula spirula (Decabrachia, suborder Spirulina), on a global geographic scaleBivariate plots for a conch height index (CHI, wh/d), b conch width index (CWI; ww/d) and c whorl width index (WWI, ww/wh). The data show that all specimens at final shell stages are wider than high. Mean values are marked by the black full circles on the vertical range linesBack to article page