78 



CHARLES BROOKOVER 



the juice. Later the colored fluid appeared at the exhalent ap- 

 erture. In this experiment the current was intermittent and 

 synchronous with the movement of the opercles in respiration, 

 but there is also, a continuous egress of water between exhala- 

 tions. This is probably due to the ciliary action to be described 

 next. 



In a pithed fish the nasal capsules were opened as shown in 

 fig. 13, by removal of the nasal bone of Allis ('97, plate xx, fig. 1). 

 When studied with a high power binocular dissecting microscope, 



.-nasal tube 



exhalent 

 aperture 7 



-mid-rib 



Fig. 13. Dorsal view of the opened nasal capsule of adult Amia to show the 

 folds of the mucous membrane. The arrows show the direction of the water in 

 passing through the nasal capsule. The water enters by the nasal tube, which is 

 anterior. X 3. 



the blood can be seen circulating laterally each way from the mid- 

 rib along the dorsal margin of each of the secondary folds, as 

 described previously for the young fish. The nasal capsules are 

 very vascular and the circulation seen here reminds one of the 

 circulation within the gills. When powdered carmine in water is 

 introduced into the opened nasal capsule, it shows a current due to 

 ciliary action directed posteriorly along the mid-rib and thence 



