496 FLYING FISHES AND THEIK HABITS. 



the rays ol" the pectoral fins and a corresponding extension of the 

 inter-radial membrane." By this amplification of surface the fishes 

 are buoyed up in the air. The pectoral fins are not used in the 

 impulse Avhich takes them out of the water; the sole impelling organ 

 is the caudal fin. The muscles of the pectoral fins of ii3nng fishes 

 are little, if any, more developed than in fishes having normally 

 strong pectorals. This weakness of the muscles operating the pec- 

 toral members contrasts remarkably with the great development of 

 the pectoral and other muscles which impart the power of real ftight 

 to bats and birds. 



A noteworthy coincidence is the limitation of flying fishes to the 

 ocean — the great expanse of waters. None are found in bodies of 

 fresh water, however large they may be, and this is equally applicable 

 to the tropical sea lake of Tanganyika as it is to the northern Lake 

 Superior. The only approximate exception has been indicated by 

 the French traveler, Jacques Savorgnan de Brazza, who claimed 

 that the little Pantodon huchholzi of the fresh waters of West Africa 

 has the faculty of emerging from the water and sustaining itself for 

 a short time in the air; thus it may be regarded to some extent as " a 

 fresh water flying fish," as Boulenger has stated. The extent of the 

 Pantodon's aerial excursions must be very limited, hoAvever, as the 

 extension of the pectoral fins is comparatively limited; in fact, its 

 excursions must be leaping rather than flying. 



This Pantodon (P. hvchhohi) is the sole known representative of a 

 peculiar African family, the Pantodontids, related to the Osteoglos- 

 sids. The only authority for considering it a flying fish is the des- 

 ignation given to it by the French traveler, Jacques Savorgnan 

 de Brazza. He obtained a single specimen at Nganchou (or (iant- 

 shu), on the Congo, while obtaining water for drinking, and it was 

 exhibited in a collection made by him as a flying fish (" petit poisson 

 volant").'' As such it is illustrated in the Cambridge Natural His- 

 tory (VII, 559) by Boulenger, Avho calls attention to it as " observed 

 by M. de Brazza to be a freshwater flying fish." The fish only 

 attains a length of about 4 inches. 



The very words of the travelers and others, whose observations have 

 been utilized, are preserved when the continuity of the narrative 

 permits. 



oThe rays to some extent correspond to or are homologous with the digits of 

 the wing of :> bat or bird, and tlie "wing" of a Hsli is therefore more like that 

 of a bat than that of a bird; the wing of tlu' Hsh, however, corresponds only 

 to the distal portion of the bat's wing — that beyond the carpel bond. 



^ Kevue Seientiliiiue, t. 38, p. IS, ISSU. 



