SWORD-FISHES. 171 



premaxillary and maxillary bones, and is an important weapon 

 of offence. The Sword-fishes frequently attack Whales, though 

 for what purpose is not clear, and so great is the strength of 

 the fish when rapidly moving that the " sword " is occasionally 

 driven into the timbers of a ship, as is shown in the specimen 

 on the floor of the case (1081, fig. 81). In very young specimens 

 of the Sword fish the upper jaw is not longer than the lower. 

 The large dorsal fin of perfect specimens is said to project above 

 the surface of the water and to act more or less as a sail. In 

 old specimens the dorsal fin is very greatly reduced in height, 

 except at the anterior end. In addition to the complete specimens 

 of Histiophorus gladius and H. brevirostris are shown a skeleton 



Fig. 81. — Part of the timber of a ship pierced by Sword-fishes. 



and a skull of H. brevirostris and the rostrum of a large Histio- 

 phorus gladius. 



Returning to the consideration of Wall-case 17, the familv Wall- 

 Bramidse is represented by Ray's Bream, Brama raii, 746 • (a ca se 17. 

 fish not related to the Common Bream, 349, Wall-case 8, nor 

 to the Sea-bream, 602, Wall-case 14), and Pteraclis velifer, a 

 fish of the Indian Ocean with remarkable enlargement of the 

 dorsal and anal fins. The family Coryphamidte includes the 

 Dolphin-fishes, the commonest species of which is Coryphcena Dolphin. 

 hippuris, 744, and fig. 82, p. 172, of wide distribution in warm seas 

 and common in the Mediterranean. These fishes have a short, 

 deep snout, not protractile ; there are no free spines in the dorsal 

 and anal fins, and the pectoral fins are inserted rather low down 



