GOBIOIDE^E. 97 



single fin, and the more lengthened form of the body. The third sub-genus Tcenloides 

 (Lacepede) contains but one species, which has a very extraordinary aspect. It has the 

 single dorsal of the Gobioides with a still longer body. The lower jaw rises before the upper 

 one, which is very short, and both are armed with long hooked teeth. The minute eyes are 

 concealed beneath the skin, and the fish inhabits the muddy bottoms of ponds in the East 

 Indies. A fourth sub-genus Periophtalmus (Schn.) contains fish of the Moluccas which have 

 the whole head scaly, and the pectorals also scaly for half their length, so that these fins 

 appear to be supported upon arms. Their gill-openings being still narrower than in the other 

 gobies, these fish can live longer in the air, and they often creep and jump upon the mud to 

 escape from their enemies in the water, or to catch the small craw-fish, which form their prin- 

 cipal nourishment. Some of them have a ventral disk like the gobies, others have the ventrals 

 separate almost to their bases. The fifth sub-genus, Eleotris, differs from the others in 

 having distinct ventrals and six gill-rays. There are species in the East and West Indies *, 

 Africa, and the Mediterranean, most of them inhabitants of fresh water, and often of mud. 



Callionymus. (Linn.) The fish of this genus have two remarkable charac- 

 ters in their gill-openings, being restricted to a hole on each side of the nape, and 

 in their ventrals being placed widely apart under the throat, and exceeding the 

 pectorals in size. Their eyes are vertical, their intermaxillaries very protractile, 

 and their preoperculum elongated posteriorly and terminating by spines. Their 

 teeth are small and crowded, but there are none on the palate. They have the 

 tubercle behind the anus, and want the caeca and air-bladder like the blennies. 

 They are pretty fish with a smooth skin, and their first dorsal, which is supported 

 by a few setaceous rays, is often very elevated. There are several species in the 

 European seas, and others in the Indian Ocean. Trichonotus setigerus (Schn.) 

 appears to be merely a very elongated Callionymus, but the gill-openings are said 

 to be fully cleft. Callionymus Baicalensis (Comephorus, Lacep.) has wide gill- 

 openings, with seven rays in the membrane, very long pectorals, and, what is a 

 peculiarity in this family, no ventrals. It is thrown up dead from the bottom of 

 Lake Baikal after a storm. 



Platyptera contains two East-Indian fish, which have the large and distant 

 ventrals of Callionymus, a short depressed head, small mouth, wide gill-openings, 

 large scales, and short dorsals placed far apart. 



* E/eotris dormitatrix. 



