416 



PAKENTAL CARE AMONG FRESH-WATER FISHES. 



for respiration meanwhile, for the vital functions are only partly sus- 

 pended. A tube is elaborated, lined with the same mucus which 

 forms the lining of the cocoon from the mouth of the fish to the sur- 

 face, and through this the Protoptere derives sufficient air to support 

 its aerial res2)iration. The presence of a fish in a cocoon may be 

 readily detected by introducing a straw into this tube. If the fish 

 be alive, quite a sharp cry may be immediately heard which is pro- 

 duced by the sudden expiration of the air from the lungs. Bou- 

 lenger, like Dubois, remarks that nothing surprises a person who has 



not been forewarned more than 

 to hear the sound that may issue 

 from a clod of earth of small size. 

 The I^rotopteres under certain 

 conditions, indeed, give utterance 

 to decided sounds. Doctor Mc- 

 Donnell received a cocoon " dug 

 up on the banks of the Gambia," 

 aud proceded to liberate the in- 

 closed fish. He pushed a straw 

 into the air hole so as to touch it, 

 whereupon it squeaked so loudly 

 as not only to give unmistakable 

 evidence of its existence, but to 

 make the doctor quickly draw back 

 " his hand, in fear lest " he 

 '^ might be bitten," and while the 

 cocoon was being sawed and 

 broken open " the animal re- 

 peatedly produced vocal sounds," 

 which McDonnell regarded as 

 " unquestionably voluntary." But 

 " after having l^een placed in 

 water it was not again heard to 

 produce any vocal sound; on be- 

 ing occasionally taken out of the 

 water it made no other sound than the smacking made by eels and 

 other fishes." The sounds were really involuntary and, as Boulenger 

 has explained, " produced by the sudden expiration of the air from 

 the lungs," reenforced by the walls of the cocoon acting as a sounding 

 board. 



The Protopteres are very voracious and indulge in a great variety 

 of food. They mostly feed on tadpoles as well as grown up frogs, 

 fishes, crustaceans, insects, and worms, but they likewise will eat 

 boiled rice and beans. In captivity they have been mostly fed on 



Fig. b. — Proloptero in coucouii. c, cocoon; c, 

 earth; /, funnel leading to mouth of fish; I. lid; 

 ni, mouth; mb, mouth of burrow; t, tail. After 

 Parker. 



