i 4 o THE WAYS OF BREATHING 



Mediterranean and in the Indo-Pacific. The 

 environment is identical ; the adaptations are 

 different according to their respective grades of 

 evolution and lines of descent. Again, in many 

 ways the Annelida are more highly organised 

 than the Enteropneusta, though the latter possess 

 gill-clefts. 



An equal degree of resemblance based on con- 

 vergence between members of distinct though 

 allied families is that of the Jumping Blenny, 

 Salarias, and the Jumping Goby, Periophthalmus. 

 These fishes habitually come out of the water, 

 the former to lounge and skip about rocks, the 

 latter upon mud and mangrove roots ; they both 

 have large goggle-eyes and both can leap about 

 as a normal mode of progression out of water, 

 while the jumping goby can also ricochet over 

 the surface of the water. As described by 

 Moseley 1 and again by Hickson, 2 Periophthalmtis 

 jumps both out of water and on the surface by 

 means of the bent, muscular, pectoral fins, of 

 course assisted by the tail. Salarias, which is 

 common on certain parts of the coast of Ceylon, 

 performs surprising leaps by the action of its 

 tail, which is kept curved when on the ground 

 ready for a spring. Any one familiar with Peri- 

 ophthalmus, which is one of the everyday sights 

 in suitable localities in the Eastern Tropics, 



1 H. N. Moseley, " Notes by a Naturalist on H.M.S. Challenger? 

 second edit. London, 1892. 



S. J. Hickson, " A Naturalist in North Celebes." London, 1889. 



