THE BLACK GOBY. 251 



fish may have struck them by accident, and not in a deliberate charge. The Sword-fish 

 generally go in pairs. 



The food of this creature is rather varied, consisting of cuttle-fish, especially the squid, 

 and of small fishes, neither of which animals would in any way fall victims to the sword. It 

 certainly has been said that the weapon is nsed for transfixing the flat fish as they lie on the 

 bed of the sea, but this assertion does not appear to be worthy of credit. 



The young and adult specimens are very difl'erent from each other. In the young, the 

 body is covered with projecting tubercles, which gradually disappear as it increases in size, 

 and when it has attained the length of three feet, they are seldom to be seen. Those on the 

 abdomen remain longer than the others. The dorsal fin extends in the young specimens from 

 the back of the head to the root of the tail, but the membranes and spines of its centre are so 

 extremely delicate, that they are soon rubbed away, and the adult specimen then appears 

 to have two dorsal fins. 



The color of the Sword-fish is bluish-black above, and silvery-white below. The whole 

 body is rough, and the lateral line is almost invisible. The usual length of the Sword-fish is 

 from ten to twelve feet, but specimens have been seen which much exceed those dimensions. 

 A few examples of the Sword-fish have been captured that measured seven feet in length. 



The Sword-fishes, family Xlpliiidoe^ have three genera and about five species. They are 

 large, strong fishes, and all good for food. Off Portland, Me., they frequent in considerable 

 numbers. The fishermen here find it profitable to fit oitt for their capture. The vessels are 

 provided with resting bars on the bow-sprit, and a lance is always at hand on the bar. "When 

 the Sword-fish is seen the fisherman hastens to his bar, and, leaning over it, to make all 

 firm, he Inirls the spear, and usually secures his prize. The handle slips out of the iron spear, 

 and the line wliich is fast to the spear-head, serves to haul the fish on board. The flesh 

 of the Sword-fish is very excellent ; rather dry, but the union of the flavor of mackerel and 

 halibut renders it quite a good food-fish. 



The Sailor Swoed-fish is still of much more curious aspect. It is a representative of a 

 genus of Sword-fishes that have been separated from the previous genus on account of the very 

 great height of the dorsal fin. 



The Sailor-Sword fish is sometimes called the Fa^s^-fisii or Sail-fish, and is said to 

 possess the power of raising or lowering the enormous dorsal fin just as a lady opens or closes 

 her fan. Sir J. Emerson Tennent mentions this fish in the following terms: "In the seas 

 around Ceylon, Sword-fishes sometimes attain to the length of twenty feet, and are 

 distinguished by the unusual height of the dorsal fin. Those both of the Atlantic and 

 Mediterranean possess this fin in its full proportions only duilug the eai-lier stages of tlieir 

 growth. Its dimensions even then are much smaller than in the Indian species ; and it is 

 a curious fact, that it gradually decreases as the fish approaches to maturity ; whereas in the 

 seas around Ceylon, it retains its fidl size throughout the entire period of life. They raise it 

 above the water while dashing along the surface in their rapid course, and there is no reason 

 to doubt that it occasionally acts as a sail." 



In this genus the ventral fins are reduced to one, two, or three spines, which in the present 

 species are two in number. The tail is very deeply forked, and the enormous dorsal fin is a 

 uniform deep blue. 



We now arrive at the large family of the Gobies, which include many curious fish. 



The Black Goby, sometimes known as the Rock-fish, is a moderately common example 

 of the enormous genus to which it belongs, and which contains more than a hundred and fifty 

 authenticated species. The members of this genus may easily be recognized by the peculiar 

 form of the ventral fins, which are united together so as to form a hollow disc, by which they 

 can attach themselves to rocks or stones at pleasure. In fact, this disc, although differing in 

 shape, acts on exactly the same principle as that of the sucking-fish. 



The Black Goby prefers the rocky to the sandy coasts, and may be found in the pools 

 left by the retreating tide. Some naturalists deny that the disc is used for adhesion, but I 



