MATUKU ISLAND. 297 



cean, Polycheles, and other animals, showing the fauna to be a 

 true deep water one, and with these a living specimen of the 

 Pearly Nautilus {Nautilus pompilius). This was the only speci- 

 men obtained during the voyage of this animal so rarely seen in 

 the living condition by any Naturalist. 



The animal was very lively, though probably not so lively as 

 it would have been if it had been obtained from a less depth, 

 the sudden change of pressure having no doubt very much 

 disarranged its economy. It, however, swam round and round a 

 shallow tub in which it was placed, moving after the manner of 

 all Cephalopods, backwards, that is with the shell foremost. It 

 floated at the surface with a small portion of the top of the 

 shell just out of the water, as observed by Rumphius. The 

 shell was maintained with its major plane in a vertical position, 

 and its mouth directed upwards. 



The animal seemed unable to sink, and the floating of the 

 shell, as described, no doubt was due to some expansion of gas in 

 the interior, occasioned by diminished pressure. The animal 

 moved backwards slowly by a succession of small jerks, the pro- 

 pelling spouts from the siphon being directed somewhat down- 

 wards, so that the shell was rotated a little at each stroke, upon 

 its axis, and the slightly greater area of it raised above the 

 surface of the water. 



Occasionally, when the animal was frightened or touched, it 

 made a sort of dash, by squirting out the water from its siphon 

 with more than usual violence, so as to cause a strong eddy on 

 the surface of the water. 



On either side of the base of the membranous operculum-like 

 headfold, which, when the animal is retracted, entirely closes 

 the mouth of the shell, the fold of mantle closing the gill 

 cavity was to be seen rising and falling, with a regular pulsating 

 motion, as the animal in breathing took in the water, to be 

 expelled by the siphon. 



The tentacular-like arms contrast strongly with those of 

 most other Cephalopods, because of their extreme proportional 

 slightness, and also their shortness, though they are not shorter 

 proportionately than those of the living Sepia. They are held 

 by the animal whilst swimming extended radially from the 



