Fig. 5From: Non-invasive imaging techniques combined with morphometry: a case study from Spirula Illustration of the ontogenetic development of the Spirula spirula shell. a Total chamber volume. b Siphuncle volume. c, Chamber volume against siphuncle surface area (CSI). d Septal angles plotted against chamber volumes show a clear three-phased trend. a–d With chamber numbers plotted on the x axisBack to article page