FLYIN(J FISIIKS AN'I) TIIKIi; IIAIJITS. 518 



vot s('( nl rest. Of course no flying lisli vnu i-aisc (hciiisclvcs in Uie 

 ;iir by means of their \vin<j:s alone." 



Schmidtlein believed that (lieii- power of flying was probably not 

 far behind that of the Exocoetids, so far as the fislies have l)eon 

 ol)served in nature, but in the aquarium experimentation on this 

 (juestion is not to be thought of. On the contrary, the authorities 

 of the Naples station have to ])rotect the basin for these (ishes with 

 bars and nets to prevent theii* escaj)ing, because they would other- 

 wise fly either through the window into the open air oi- to either side 

 into the adjoining tanks. And, as a matter of fact, the station loses 

 a rather large number of the Hslies because they jump out and fall 

 against the walls, or on the bridge over the aciuarium, and perish 

 there. 



II. 



The Dactylopterids are naturally carnivorous, but their food is 

 determined by the size of the mouth and their environments. Ac- 

 cording to Schmidtlein, their snuiU mouth permits them to swallow 

 only small morsels; therefore they like to take crustaceans, such as 

 shrimps {Crangon or Chkjo) and prawns {Palaemon) , young crabs, 

 and tiny fishes, which they find dead on the bottom. 



III. 



W. P. Calderwood and G. P. Bidder told Ernest Holt (18J)8) " that 

 when a Dactylopterus was placed in a tank at Naples containing 

 some small sharks the latter bit pieces out of its pectorals, a liberty 

 resented by violent grunting." It is added that "gurnards and 

 dories also grunt under circumstances of discomfort, the sounds 

 being of the nature Avhich appears from experiment to be pi'rceptible 

 by fishes. They may possibly subserve a function which is in part 

 protective."' 



The Dactylopterids emit sounds under certain conditions, botii in 

 the water and out of it. While Calderwood was killing a couple of 

 specimens "sounds exactly similar to those of the Ournard were 

 distinctly heard, and simultaneously with each sound a distinct con- 

 traction of the bladder could be felt from the exterior. These con- 

 tractions w^ere quite independent of any movements of the mouth or 

 operculum." Schmidtlein never heard the sounds emitted voluntarily 

 under w^ater, nor observed the movement of the gill covers which 

 ])roduce them. Experiments relating to tliis subject weiv nnide by 

 him and details promised for another ])lace. but never published. 

 The testimony of Calderwood and P)i(lder. however, supi)lies the defi- 

 ciency in Schmidtlein's observations. 



The sounds thus noticed are produced by the action of four nuiscles 

 SM 1904 33 



