Fig. 5. (A–C) Micrographs used to measure the density of jellyfish microfibrils. Micrographs taken with a video capture system using a 40x objective on an interference contrast microscope. Samples were allowed to dry down for an hour before measurements were taken, to facilitate focussing the microscope. Fibres were branched at both ends, more so at the medial end, near the gastrodermal lamella. (A) Near the exumbrellar surface. (B) Mid bell. (C) Near the gastrodermal lamella. Fibre density was determined by counting the number of fibres crossing the black line across the micrograph. Micrograph width: 640 pixels=128 µm. Depth of sample: 500 µm. (D) Digital micrographs taken with a 100x objective on the interference contrast microscope show that fibre diameter increases slightly with body size. For improved accuracy, measurements were made with a 15x filar micrometer eyepiece mounted on the microscope. (Inset) Approximate locations and orientation of samples are indicated by the coloured boxes: red, A; blue, B; green, C; magenta, D.