The presence of mudskipper eggs in an air-filled chamber was confirmed by direct endoscopic observation of intact burrows of Periophthalmodon schlosseri in a mudflat in Penang, Malaysia. For all five burrows from which video images of egg chambers were successfully obtained, the presence of air was unequivocally demonstrated by the existence of an air-water interface inside the chambers. Of these burrows, eggs were found in two, but not in the others. Eggs were laid uniformly in a monolayer on the inner top surface of the chamber. The much brighter color of the surface mud of the egg chambers than the surrounding mud, irrespective of the presence or absence of the eggs, suggested that the surface mud had been oxidized by deposited air.

Eggs of the giant mudskipper, Periophthalmodon schlosseri were collected from a burrow in Penang, Malaysia, in November 1998, and hatched larvae were reared in the laboratory. The eggs were demersal with adhesive filaments and elliptical in shape (0.83-1.43 mm in long-axis diameter). Newly hatched larvae (2.1-2.6 mm in notochord length) possessed a yolk sac. The number of myomeres was 10 ϩ 17 ϭ 27. The mouth and anus were already opened. The larvae started feeding one day after hatching and completely absorbed the yolk by the third day at a water temperature of 24.5-28.0°C. Key words Eggs and larvae · Mudskipper · Oxudercinae · Periophthalmodon schlosseri · MalaysiaPeninsula, Malaysia. Eggs and newly hatched larvae were reared for nine days in four aquaria (3.5-10.6 l) under natural light conditions at the Universiti Sains Malaysia (USM), Penang, Malaysia. The rearing water was 50% seawater (14-17‰) with gentle aeration; the temperature ranged from 24.5° to 28.0°C (mean, 26.8°C). Rotifers (Brachionus spp.) were supplied to larvae immediately after hatching.Micrographs of live eggs and larvae were taken using a camera attached to a binocular microscope at USM. From one day after hatching, approximately 10-20 larvae were fixed with 5% formalin each day. The following characters of the micrographs and fixed specimens were measured using a digimatic caliper to the nearest 0.01 mm under a profile projector at the University of the Ryukyus, Okinawa, Japan: notochord length (NL), yolk-sac diameter in long axis (YL), head length (HL), and eye diameter (ED). Specimens are kept in the Department of Marine Sciences, University of the Ryukyus (URM). Results and DiscussionThe eggs collected from the burrow. Eggs were deposited sparsely in a single layer on the ceiling of the inner chamber of the burrow; they were demersal with a clump of adhesive filaments at one end of the egg membrane (Fig. 1A). Eggs were elliptical, 0.83-1.43 mm (mean Ϯ SD ϭ 1.02 Ϯ 0.12 mm, n ϭ 36) in the long-axis IchthyologicalResearch

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