276 



OUT OF DOORS. 



with the time occupied in hatching. In this establish- 

 ment, where the water is kept at a tolerably uniform 

 temperature of 45 Fahr., the commencement of the 

 process is visible in fifty-five days, the action of the heart 



OPEN-AIR TROUGHS, 



being perceptible even to the naked eye, and a sin- 

 gularly beautiful object under the microscope. 



When first hatched the young fish is a most 

 curious little object, having a thin, long, transparent 

 body, hardly visible when immersed, and bearing the 



