366 SPINY-FINNED GROUP. 



from taking a bait by swimming round them and enticing them away ; but all 



these appear to be pure fictions, and perhaps the best account of the real habits of 



the fish is one by Dr. Meyen, from which the following summary is taken. It 



appears that the pilot-fish constantly swims in front of the shark, sometimes 



coming close to its muzzle or front fins as it approaches a ship, and sometimes 



darting sideways or forwards for a short distance, and then returning to the side 



of the larger ship. In one instance, where a baited hook was thrown over the 



ship's side, the pilot-fish rushed up, and after swimming close to the bait, returned 



to the shark, and by swimming and splashing round it appeared to be attracting 



its attention. Soon after the shark began to move, with the pilot-fish in front, and 



was almost immediately hooked. Instead of the pilot-fish taking care of the shark 



it would rather seem to frequent the company of the latter for the sake of the 



fragments of food and other substances to be found in its neighbourhood ; and it is 



doubtless for the same reason that these fishes follow ships. In summer, pilot-fish 



will not unfrequently accompany vessels into the southern British harbours ; but 



their purely pelagic habits are indicated by the circumstance that their spawn 



and fry are found far out in the open sea. The young both of this fish and of 



some of the allied forms are so different in appearance from their parents that 



they have been described under distinct generic names. 



Both the preceding; genera belong; to a group of the family in 

 Sea-Bats. . . x tete , to ,,. P . 



which the spines of the anal fin are detached from its soft portion. 



As an example of a second group in which these two portions are connected by 

 membrane, we may notice the so-called sea-bats (Platax), remarkable for the great 

 height and compression of the rhomboidal body, and the strong development of the 

 dorsal and anal fins, which are often nearly similar in form and size. Indeed, 

 except that they are symmetrical and have an eye on each side of the head, the 

 sea-bats look almost like flat-fishes. They have the sj)inous portion of the single 

 dorsal fin almost concealed, and with from three to seven spines ; the anal has 

 three spines ; and the pelvic fins, which are sometimes greatly elongated, have a 

 single spine and five rays. The scales are rather smaller or medium ; the palate is 

 toothless ; and the jaws have a series of outer teeth somewhat larger than the 

 small ones of the inner rows. These fish, of which there are but few species, appear 

 to be confined to the Bed Sea, Indian Ocean, and the Western Pacific, where they 

 are abundant. Some of them attain a length of about 20 inches, and the body may 

 be marked by a few broad vertical dark bands, the long lobes of the fins being black. 

 In young specimens the rays of the median fins are proportionately much longer 

 than in adults, thus giving the whole fish somewhat the appearance of a cheese- 

 cutter. Sea-bats are found in a fossil state not only in the middle Eocene of Monte 

 Bolca, but likewise in the Cretaceous rocks of England and the Lebanon, so that the 

 genus is an old one. In the allied genus Psettus, from the coasts of Western Africa 

 and the Indo-Pacific Ocean, the pectoral fins are rudimental. 



The Dories, — Family Cyttid^-e. 



The deep form of the compressed body, the division of the dorsal fin into two 

 distinct moieties, and the circumstance that the number of trunk-vertebras exceeds 



