The Comatulids of Torres Strait. 113 
theless it was clear that long arms in front, short arms behind, gave the 
normal method of progression. It may be a fair inference that the 
asymmetrical condition of the arms is the result of selection, since it 
is possible that long arms would be better for pulling and short, stout 
arms for pushing. But it is no doubt true that there are very diverse 
interpretations of the matter possible, and it is no part of my purpose 
to discuss the subject here. The statement of the facts given above 
is beyond dispute, however. 
Locomotion in all the comatulids observed at Maér, whether swim- 
ming or creeping, invariably takes place with the oral surface upper- 
most. If dropped in deep water with the mouth down they commonly 
righted themselves before reaching the bottom. If not, or if placed 
on the bottom with the mouth down, they slowly but surely turned 
over before attempting to either swim or creep. The process of turning 
over is essentially the same as in a starfish. That is, a group of arms 
begins the task and continues gradually lifting up one side until the 
arms of that side can be bent back far enough over and beyond the 
aboral surface to secure a hold. Then by their pulling and the pushing 
of the arms opposite to them, the disk is righted. The process seems 
a tedious one and is probably not often necessary in the normal life 
of comatulids on the reef. 
Particularly interesting is the question of how much these comat- 
ulids move about under the natural conditions of their life, but no 
satisfactory evidence on the point was secured. On one occasion a 
dozen healthy comatulids of four species were ‘‘planted”’ on a part 
of the reef where no crinoids were living. Twenty-four hours later 
they had all disappeared and no trace of them could be found in the 
neighborhood. But as there had been a strong wind and much surf 
during the night, they may have been simply swept away. On another 
occasion 10 large comatulids were carefully located around the margin 
of a rock-fragment about a meter in diameter. Circumstances, includ- 
ing unfavorable tides, made it impossible to visit the spot again for a 
week. Then it was found that more or less sand had washed in around 
the rock and the comatulids were apparently gone, but again there 
was doubt what part the surf and strong tidal currents may have 
played. Crinoids dropped beside the live-car, on reaching the bottom, 
began at once to move away and continued moving, usually in a fairly 
straight line, until they reached a rock beneath which they could find 
shelter, but it was not possible to determine their ultimate resting-place. 
During these experiments I was much struck by the attitude of 
fishes towards the crinoids. Fishes of many species were abundant 
in the water just outside the reef and their movements were easily 
noted. Any object dropped in the water at once attracted their 
attention and if edible was nibbled at or seized outright. Comatulids 
were always noticed, but were never touched either in the water or 
