Fig. 2. (A) Scanning electron micrograph of the statocyst from a 43 mm P. serratus showing the solitary sensory seta (sss) positioned away from the organised row, a feature present on each specimen examined. A small amount of otolithic material (om) can be seen on the dorsal surface of the statocyst. hc, hair cell; oc, outer crescent; sc, sensory cushion. (B) Close-up of a typical row of sensory setae present on all statocyst samples, viewed from above with the binding mucous removed. hcb, hair cell base; us, upper tapering section of hair cell; tlp, thread-like projections.