1868.] DR. F. DAY ON INDIAN FRESHWATER FISHES. 279 



from the receptacle by pressing upon the superior branchiae. Most 

 of the air was discharged, and the sj)ecinien was placed, like the 

 others, under the diaphragm. But death did not ensue; it re- 

 mained in a sluggish state for seven hours at the bottom of the 

 globe, not even attempting to rise and obtain air. At the end 

 of this time another fish was placed in the same globe without having 

 had the air removed from the receptacle, whilst the first specimen, 

 without being allowed to rise to the surface, had the gills opened, 

 and the whole of the air (if there was any) remaining in the cavity 

 abstracted by means of a syringe with a long pipe. The new arrival 

 appeared to arouse the previously dormant fish into activity, and 

 they both dashed wildly about, but died within two hours. The 

 exertion no doubt caused excitement of the circulation, necessitating 

 a larger supply of air. On opening their gills under water no air 

 escaped, thereby proving that it is not generated beneath the water. 



Experiment No. 6. — A bandage was stitched pretty tightly around 

 the head of another specimen of the same species at 8 a.m., so as to 

 entirely prevent its opening its gills, care having been taken not to 

 obstruct its eyesight. It was then placed in a globe of water ; but 

 this process did not appear to inconvenience it in any way, and after 

 submitting to it for 24 hours, it was as lively as possible. In this 

 case it was impossible that the gills could have been opened ; the fish, 

 therefore, must have sustained life by aerial respiration. 



Experiment No. 7. — The same fish, without the bandage havinc 

 been removed, was, after the lapse of this time, viz. 24 hours, placed 

 in water beneath a diaphragm, in company with another which had 

 been in the same vessel with it all the previous day. In the space 

 of half an hour the bandaged fish died from being unable to pass 

 water through its gills. After death the cavity contained no air. 

 The other specimen lived for 1 7 hours in a sluggish state, rarely 

 moving at the bottom of the globe, showing, as in experiment No. h, 

 that these fish can live in a quiescent state for some time in water 

 although aerial respiration is precluded, and that they must there- 

 fore be able to take in a certain amount of air from the water by 

 means of their branchiae, although not in sufficient quantity to sup- 

 port life for more than a limited period. 



Experiment No. 8. — A bandage was stitched round the head of a 

 Macrones tengara, a water-breather, in the same manner as in the 

 last experiment. It died in 34 minutes ; but in this instance the 

 gill-opening could not be entirely closed, owing to the serrated pec- 

 toral spine being beneath it. 



Experiment No. 9. — A specimen of Ophiocephalus punctatus was 

 placed in a dry cloth at 9.5.5 a.m., and left without any moisture, 

 the temperature being at 76° Fahr. It lived until 1.20 p.m., occa- 

 sionally opening its mouth and taking in air. At 12.1.5 it was able 

 to move across the table, whence it fell on to the ground, and 

 was only picked up after it had proceeded several feet across the 

 room. This fall in its dry state may have injured it and hastened 

 its death. At all events it lived entirely without moisture for three 

 hours and twenty-five minutes ; and it is doubtful whether it did not 



