BONY FISHES AND GANOIDS. 477 



nest for the reception of the eggs. Of greater interest are the mud-skippers, 

 or hopping-fish, on account of their strange habits, and the long time they 

 can remain out of water. They are found on the coasts and estuaries of West 

 Africa, and the countries bordering the Indo-Pacifio Ocean. Owing to tlieir 

 remarkably prominent eyes, they look very much like tadpoles ; the common 

 species having its dorsal fins spotted with brilliant blue. The pectoral fins 

 are very strongly developed, and are used, when the fish is out of water, for 

 walking or climbing on the roots of mangrove trees. Dr. H. O. Forbes writes 

 that "if the observer remain quite still, the Periophthalmus will sit motion- 

 less, staring at him with his great eyes, except that every now and then it 

 will wink apparently, sometimes with one eye, and sometimes with both to- 

 gether. What seems to be winking, however, is the inversion of the eye into 

 a depression immediately under it, for the purpose of lubricating the organ 

 when it begins to become dry. The habit that most impresses the naturalist 

 encountering these fishes for the first time is the long period which they can 

 remain out of the water. The writer has timed individuals, both in their 

 native state and in the aquarium, to sit for more than half an hour without a 

 bath. They would then walk slowly into the water, immerse themselves over 

 the head for a second, emerge and remain resting for a short time, with the 

 head and shoulders above, and the mouth under the surface, and walk slowly 

 out again on to the margin. This fish rarely if ever, goes beyond its depth, 

 and only for a few seconds does it at any time completely submerge itself. 

 Their usual habit is to sit propped up on their stiff ventral and strong pectoral 

 fins, with the fore-part of the body elevated, and their quick mobile eyes con- 

 spicuous and inquiring ; either, as already remarked, entirely away from the 

 water, or with only the extremity of the tail dipping in. When out of the 

 water and sitting stUl, the mouth is kept closed, and no motion can be de- 

 tected in the gills or gill-covers. Every now and then the eyes are moistened 

 as described above, and the fish flaps its pectoral fins across the gill-covers 

 and the hind-part of the head. When the tide has just receded and the small 

 marine animals are beginning to follow it, tliey are very busy darting here 

 and there in pursuit, and gobbling them up voraciously. They will even 

 attack and eat smaller members of their own species. When moving forward, 

 they 6ar themselves on their strongly muscular pectorals, which they use 

 simultaneously when hopping, or alternately in their more deliberate ' walk- 

 ing,' which leaves a curious triple track on the soft mud which they have tra- 

 versed. When in the water the Periophthalmns sits on the bottom in the 

 same attitude as on shore, with its upper-lip submerged, but with the rest of 

 the head and upper part of the back exposed, the water being driven over its 

 gills very slowly and deliberately as compared with the common trout in an 

 adjoining tank. Its eyes are better adapted for sight out of than under water, 

 and are capable of seeing all round." 



The curiously-shaped marine band-fishes form the first representatives of a 

 section which includes five other families. In this section the body is low, 

 elongate, and either subcylindrical or compressed ; the dor- 

 sal fin being very long, with its spinous portion — when dis- Section Elennii- 

 tinct — equal to, or exceeding the soft part in extent. Indeed, formes. — Family 

 in some cases the whole dorsal is composed of spines. The CepoHdce. 

 anal is more or less elongated ; the caudal — when present at 

 all — is rounded or somewhat truncate ; and when the pelvic tins are aeveloped, 

 they may be either jugular or thoracic in position. The band-fishes {Cepola) 

 — ail of which are of small size— take their name from the long compressed 



