THE GVBY FAMILY. 187 



these being the prominent eyes, placed close together at the 

 summit of the head, and the large pectoral fins with their 

 highly-muscular bases with which their hopping and climb- 

 ing are chiefly accomplished. In the words of Saville-Kent, 

 the Mud-Skipper "is an essentially-tropical species, being 

 particularly abundant among the muddy mangrove-flats of 

 North Australia and the Malay region. Under these con- 

 ditions, it may be commonly seen at low water associating 

 in little groups and basking in the sun on the surface of the 

 mud. chasing each other in sport with their quaint skipping 

 action ; or, having climbed to the elevation of a mangrove 

 root or the woodwork of the jetty, peacefully contemplating 

 its companions' antics. The capture of the little fish seems 

 at first sight an easy task ; but woe betide the reckless en- 

 thusiast who ventures on the treacherous ooze in its vain 

 pursuit. He will emerge from the enterprise with bemired 

 raiment and a much-chastened spirit. Should, however, the 

 acquisition of specimens be an important object, the enlisted 

 services of the wily native who needs but a little paint 

 and a pearl-shell for the renewal of his full-dress apparel 

 will speedily secure an abundant supply. 



"A remarkable circumstance associated with the life 

 economy of Periophthalmus is the fact that it cannot sus- 

 tain life if continually water-submerged like ordinary fish. 

 The exposure of its tissues to the action of atmospheric air 

 with every fall of the tide appears to be essential to its well- 

 being, and examples experimentally kept under water for 

 prolonged intervals were literally drowned. As a provision 

 for its abnormal life-habits, it has been ascertained that 

 Periop/ithaliinis possesses a supplementary respiratory organ 

 which, singularly to relate, is represented in this instance, 

 in the creature's tail. The fish while reposing on the sur- 

 face of the mud commonly leaves its tail more or less im- 

 mersed in the water. The blood circulates with abnormal 

 energy through this thin membraneous appendage, which 

 accordingly fulfils the function of a supplementary gill." 



Periophthalmus austral is grows to a length of about 

 12 inches. 



The Eel-like Goby is a fish which might be mistaken 

 by many, for an Eel : but the presence of ventral fins will 



