FIJI-NEW ZEALAND EXPEDITION 63 
being undoubtedly capable of acting as a medium for the ex- 
change of the oxygen in the air outside for the carbon dioxide 
brought by the blood to the gill lamelle. The gill filaments, more- 
over, seem stiff enough to prevent their matting together when 
out of the water. There is quite an evident analogy between this 
apparatus for breathing air and that of the land crabs. In the 
latter the water contained in the bottom of the branchial chamber 
is applied to the gills by a brush-like modification of the scaphog- 
nathite or ‘‘bailer,’’ while in Periophthalmus the gills, if I am 
right in my interpretation of the muscular structure, can be 
periodically dipped into the water at the bottom of the chamber 
analogous to the branchial chamber of the crab. 
The preserved specimens were not suitable for the study of the 
swim bladder, nor am I sure from a somewhat hasty examination 
that they have this organ in functional form. This little fish 
must spend a good deal of time out of the water and seems quite 
intent on contemplating the scenery. Professor Thomas, who 
secured the specimens we brought home with us, says that the 
Fijians call this climbing fish ‘‘tiloko.’’ He adds, ‘‘It moves over 
the water by a series of short rapid jumps, can climb up out of 
the water on to the sticks and stones and stay there ten minutes 
or more. It is very hard to capture. Two of them jumped out 
of a pail on the floor of the house and it took Glock and myself 
several minutes to catch them. It was like catching lively 
crickets. ’’ 
In their ‘‘Fishes of Samoa’’ the authors say: ‘‘It (Perioph- 
thalmus) abounds especially in muddy bayous, freely leaving the 
water to climb bushes, to skip through the grass or to lurk under 
piles of stone to await the returning tide. It is exceedingly quick 
of movement and very tenacious of life. Specimens placed in a 
pail of formalin escaped when the lid was raised.’’ 
Most of the members of the family to which this strange creature 
belongs, the Gobiidz, are dwellers along the rocky flats and shores 
that fringe the tropical islands of the Pacific. When the rocks 
are bare at low tide these little gobies slither across the surface 
of the flats with remarkable agility and retreat to the crevices and 
cavities in the rock masses where they often, perhaps habitually, 
remain until the return of the tide. Thus they have gradually 
developed an ability to travel rapidly over bare ground and to 
3 Fishes of Samoa, Jordan and Seale, 1906, p. 394. 
