Fig. 1. (A) Experimental set-up for ventilatory analysis by video recording. Animals were free ranging in a vertical layer of natural sediment, cardiac and ventilatory activities were measured by visual inspection through the animals. Analyses were performed under dim light by means of infra-red (IR) camera and micro-spotlight (see text for details). (B) Mini-aquaria with myodocop nest. Scale bar, 1 cm. (C) Experimental procedure of short-term exposures at various oxygenations numbered from 1 to 10.