LOWER COASTAL ANIMALS I29 



which Stiff-armed brittle stars (Ophiura) are particularly prominent. To 

 move about among stones and blocks of coral with five such rigid arms 

 would be impossible, but they are admirably adapted to the soft, level 

 bed. Here also we found heart-urchins, many kinds of worms, and some 

 molluscs (Nucula and others). In the Strait of Macassar the quantities 

 of empty shells on the bottom had facilitated the growth of a rich epifauna 

 which included the feathery black corals (Antipatharia), large and hand- 

 some kinds mostly occurring in deeper waters. Here were polyps (Nema- 

 tophanus), on which were brittle stars (Euryale), their arms twined 

 tightly round the stalks of the polyp colonies, numbers of sea-mats or 

 polyzoa, and various feather-stars. 



It was seldom that we had opportunities for trawling in such shallow 

 water. A little more often we were able, in out-of-the-way places, to 

 explore the edge of the continental shelf between 50 and 200 metres deep. 

 I remember a day in the Great Australian Bight when the grab was 

 lowered to 80 metres. Although it closed in the normal manner, it was 

 found when hauled up to be empty of bottom material, and so was 

 classed as "non-quantitative", which is the worst that can be said of a 

 bottom sample. However, I proceeded to sort the little that it did con- 

 tain; and the more I examined it, the more interesting I found it to be. 

 Evidently the grab had struck a pure rock bottom, more or less clearing 

 it of fauna over the area of 0.2 square metre which it spanned, and 

 so enabling us to form an impression of its appearance. The bottom had 

 been covered with finely branched organisms which resembled red algae 

 but proved to be a mass of polyzoa colonies. These "growths" are inhabited 

 by brittle stars, rare sea slugs (Doridunculus), isopods, and various other 

 crustaceans, among them the squat lobster (Galathea), which resembles 

 a small, slender, reddish crayfish but is much more active. From other 

 trawls on the same kind of floor we know that we may expect to find the 

 beautiful feather-stars (Comatula), either clinging to the rock or lazily 

 whisking themselves through the water with their feathery arms. 



At a point near by, our echo-sounder seemed to indicate a level bottom 

 of about the same depth, and so we risked our new construction, the six- 

 metre-wide sledge trawl which carries two parallel three-metre bags. There 

 is always a hope that one of these will come up, even though the other 

 should break, and so it turned out on this occasion. One bag was missing 

 and the other was badly torn — fortunately in a way, because the "little" 

 that remained was enough to fill several large tubs. On this sandy bottom 

 there had been a low "undergrowth" of animal sponges in a great variety 

 of forms and brilliant colouring, in which a bright orange predominated. 



