109 



Order III. — LYOMERI. 



In the line of specialization of the eel-like forms, we now come to a group of 

 the most extraordinary development. There is a " looseness " about them which has 

 given a name to the order — Lyomeri. The branchial arches are reduced to very simple 

 bars, five in number, on the sides of the oesophagus, and have no connection with the 

 cranium; the supraniaxillary bones alone are developed, and have a ligamentous con- 

 nection with the cranium ; the palato-pterygoid arch is entirely wanting ; and the sus- 

 pensorium for the lower jaw is composed of only two pieces, the hyomandibular and 

 quadrate, of an elongate, subcylindrical form, and connected with the skull by a 

 movable joint which allows it to be swung in various directions. Two families of the 

 order have been discovered, the Eurypharyngidte and Saccopharynsidfe. 



The EuRYPHARYNGiD^ Were unknown till 1882. In the last month of that year 

 the French 7iaturalist Vaillant described a species as Eurypharynx pelecanoides, and 

 the next year another was made known by Gill and Ryder under the name Gastro- 

 stomi/s baircUi. These fishes inhabit the deep sea, and are esjieeially remarkable for 

 the excessive development of the jaws and the oral parts generally. The jaws of 

 Gastiostonnis are six or seven times as long as the flat squarish cranium, and the in- 

 tramandibular pouch has the resemblance to that of the pelican which induced Vaillant 

 to give the name pekcanoides (pelican-like) to the fish he described. Of course nothing 

 is known, from observation, of its habits, but it is probable that tlie fish swims consid- 

 erably over the Iwttoni, and that it feeds with open mouth, taking in the water and 

 contained organisms, and keeping the latter in by the interlocking teeth, which would 

 apparently act like the whalebone of the mysticetc whales. Its principal food is doubt- 

 less the small animals swimming at large in the horizon it inhabits, — crustaceans, 

 foramenifers, etc. It is not at all likely that it troubles fishes approximating it in size. 



