3 68 SPINY-FINNED GROUP. 



characterised by the absence of pelvic fins in the adult ; the dorsal and anal fins 

 being long, with their points curving backwards in several of the species, and 

 the caudal deeply forked. In habits these fishes are partly pelagic. 



The second of the two families is represented typically by the 

 coryp senas. we i]_k nown pelagic coryphasnas (Coryphcena), popularly miscalled 

 dolphins. As a family, the Coryphcenidce are readily distinguished from the 

 Stromateidce by the absence of tooth-like processes in the oesophagus. In the 

 typical genus the body is somewhat elongated and compressed, the adults having 

 an elevated crest on the top of the head ; and the cleft of the mouth is wide. 

 The sino-le dorsal fin extends in a nearly straight line from the back of the head 

 almost to the deeply-forked caudal ; the anal resembles the dorsal in having no 

 distinct spinous portion ; and the well-developed pelvic fins are thoracic in position, 

 and can be received in a groove in the abdomen. Teeth are present in the jaws, 



as well as on the 

 vomer, palatines, and 

 tongue ; the cycloid 

 scales are small ; and 

 there is no air- 

 bladder. The cory- 

 phsenas, of which 

 there are some half- 



CORYPH.ENA. 



dozen species, are 

 purely pelagic fishes, ranging over all temperate and tropical seas, and remarkable 

 for the beauty of their fleeting colours. Dr. Giinther observes that so " far as the 

 colours are capable of description, those of the common species (C. hippurus), which 

 is often seen in the Mediterranean, are silvery blue above, with markings of a 

 deeper azure, and reflections of pure gold, the lower-parts being lemon-yellow, 

 marked with pale blue. The pectoral fins are partly lead colour, partly yellow; 

 the anal is yellow, the iris of the eye golden. These iridescent colours change 

 rapidly whilst the fish is dying, as in the mackerel. The form of the body, and 

 especially of the head, changes considerably with age, Very young specimens, 

 from 1 to 6 inches in length, are abundant in the open sea, and frequently 

 obtained in the tow-net. Their body is cylindrical, their head as broad as high, 

 and the eye relatively very large, much longer than the snout. As the fish grows 

 the body is more compressed, and finally a high crest is developed on the head, 

 and the anterior part of the dorsal fin attains a height equal to that of the body." 

 This species ranges over all tropical seas, and attains a length of from 5 to 6 feet ; 

 although its flesh is unpalatable to Europeans, it is eaten by the natives of 

 Madras. Powerful swimmers, and associating in large shoals, coryphamas are 

 determined enemies to flying-fish, pursuing them as they skim from wave to wave, 

 and capturing them as they again fall into the water. 



As an example of genera in which the body is much compressed, 



short, and deep, we may select the sun-fish (Lampris lima), of the 



North Atlantic and Mediterranean, the sole representative of its genus. The 



body is covered with very small deciduous scales, the mouth has a narrow cleft, 



and is devoid of teeth, the dorsal has its anterior portion elevated into a narrow 



