Though the relationship is well defined, the shark makes no distinction in favour of the ray when in pursuit of food. Indeed, certain members of the predatory family seem to delight chiefly in a diet of rays, and perhaps as a result of this persistent pursuit has the shape of the latter been evolved, since it enables them to take refuge in water so shallow that even a small shark would inevitably be stranded. Timorous by nature, the smaller rays parade the beach-line, while the larger are better able to hold their own in deep water. Although as a rule solitary of habit, there seem to be occasions on which rays become gregarious, when a considerable extent of sandy shallow has been observed to be actually paved with motionless but vigilant individuals, the edge of the "wing" of one overlapping that of the next with almost perfect regularity. The monstrous grey-striped tiger shark (GALEOCERDO TIGRINUS) in my experience generally keeps to deep water and hunts singly; but a recent event sets at naught other local observations and at the same time provides graphic proof of the rapacity and hardihood of the species. About a hundred yards out from the beach, as we started on a strictly sordid beachcombing expedition to the scene of the squashed wreck of a Chinese sampan, a shark betrayed itself by the dorsal fin quartering the glassy surface of the sea. Equipment for sport consisted of an axe, a crowbar, a trivial fish spear, and a high-velocity rifle. Pulling out noiselessly, a trail of oily blood was intersected and the next moment a huge shark appeared, carrying in its jaws a black ray, which it mouthed unceasingly.