338 Dr. J. E. Gray on the Swordfish of the Indian Ocean. 



XLIII. — On the Injury inflicted on Ships hy the Broad-finned 

 Swordfish of the Indian Ocean. By Dr. J. E. Geay, 

 F.R.S. &c. 



The Swordfish of the Indian Ocean, which forms the genus 

 HistiojyhoruSj on account of the large high dorsal fin, has a 

 gradually tapering, nearly cylindrical, bony beak, covered with 

 granular skin. These fishes swim exceedingly fast ; and when 

 they come into contact with a wooden ship, the beak pierces the 

 timbers, which so closely embrace it that the animal can only 

 disengage itself by breaking away from its snout; for the 

 longer the time that it remains attached, the more firmly it 

 becomes fixed, from the swelling of the wood and the fibres 

 of it attempting to regain their natural position. We have a 

 specimen of the snout fixed in the planks of a ship, in the 

 British Museum ; and I have seen two or three specimens of a 

 similar kind, aU showing the very firm manner in which the 

 snout is fixed in the wood, and that the snout had been broken 

 from the head of the animal, caused, I believe, by the shock 

 of the collision. 



The hole made in a piece of wood by an awl or the conical 

 beak of a swordfish simply presses the grain of the wood aside 

 for its passage, so that when the body is removed which 

 formed the hole, the fibres, especially when soaked in water, 

 strive to regain their natural position, and the hole so made is 

 more or less completely filled up and obliterated. 



It is even the same with a bullet or cannon-ball, which 

 either forces its way through a kind of crack in the wood, or 

 regularly breaks away a part of the wood, or crushes it, leav- 

 ing a very irregular hole. The only way in which a clear 

 circular hole can be made in a plank of wood or side of a ship 

 is by an auger or centre-bit, which removes the wood that 

 filled up the hole : such a hole may contract in size, but it is 

 never filled up by that contraction, as part of the substance 

 has been taken away. 



I therefore think that we may conclude that, when a broad- 

 finned swordfish comes into collision with the planks of a 

 ship, it forms a hole or, rather, slit which contracts on the 

 beak and does not allow the escape of the fish so as to leave a 

 circular hole in the ship's side. This is important, because a 

 few years ago there was a trial of an insurance case where a 

 circular hole was found in one of the planks, by which the 

 cargo was injured. It was contended on one side that this 

 hole was formed by the beak of a broad-finned swordfish ; and 

 this view was supported by a very celebrated comparative 

 anatomist and a popular writer on natural history, and was 



