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ANNALS NEW YORK ACADEMY OF SCIENCES 



attachment at the center of the posterior edge of the plate to the anal fin. 

 It is evident that the fish is able to create a suction pressure in the re- 

 gion of the plate, though how this is accomplished is not apparent from 

 the structure. 



By means of the alternate action of the mouth and of this curious 

 apparatus, the fish is able to creep against a current that would baffle 

 its efforts entirely, if it relied alone upon its fins and tail. When it 



Orifices for the 

 Inflow of water 

 to Gills 



Via. 3.— A) yes marinoratus Regan; dorsal view 



is engaged in creeping or in sticking fast to some object, the sucker 

 mouth necessarily is closed. It is evident that the gills must be sup- 

 plied with the life-maintaining flow of water through some other avenue. 

 At the upper extremity of each gill slit there is an orifice provided with 

 a valve opening inward (Figs. 1 and 3). During the diastole of the gill 

 covers, the water flows inward through the orifices and is expelled 

 through the gill slits during the systole. 



