226 THE ANGLEE-NATUEALIST 



series of small jerks, — its motion when advancing resem- 

 bling it is said that of a two-footed lizard. The body 

 of this fish is enveloped in strong plates, which, like those 

 underneath the serpent, probably facilitate its progress ; 

 and the Indians afiirm that it is furnished with an 

 internal reservoir of water sufficient for its journeys, so 

 that the body, even if wiped dry with a cloth, imme- 

 diately becomes moist again. This assertion there seems 

 to be no reason to doubt, as analogous provisions are 

 observed in several other migratory species : one of the 

 Plying-fish, and a species called ' Swampines,^ belonging to 

 the genus Hydrargyra (discovered by Bosc in the fresh 

 Avaters of Carolina), are furnished with a membrane which 

 enables them when travelling to close the mouth and 

 gills, thus retaining moisture sufficient for short trajets. 

 These journeys the ' Swampines ' perform by leaps, fre- 

 quently in droves of thousands together, directing their 

 course with unerring instinct towards the nearest water, 

 and furnishing, during their migrations, food for a vast 

 number of birds and reptUes. Their organ of motion 

 is a long rough-edged spine, situated as in the Mat-headed 

 Hassar. The 'Dorcas' of Guiana*, and several species be- 

 longing to Siamt, also progress by much the same means. 

 Of the travelling-fish of Ceylon the most common is a 

 sort of Perch, called by the natives Kavaya, which grows 

 to the length of about 6 inches, having its head round and 



* Sir E. Schombm-gk's Fishes of Guiana. 

 t Sir J. Bowling's Siani, vol. i. p. 10. 



