324 JOURNAL, BOMBAY NATURAL HIST. SOCIETY, Vol. XXIV. 



give us splendid ova, but a male trout in India is at his best when one year 

 old, and his milt " goes off" after the third year. 



Sticfinci Boarc/s 



Screen, -i Z/'ac 



F/p://{b) 



/f^fcA/hjf Troag^A 



/ fi^anking 



(ii) Eyeing. — The green eggs must be picked over daily and with 

 extreme care, for at this stage the slightest shock will kill them. Those 

 which are unfertile or in which the embryo has been killed turn white and 

 will infect the whole hatch with fungus unless they are at once removed. 

 If the water temperature is 50° F. the eye of the fish will appear in 23 days 

 at 54° in 15 days, at 41° in 49 days. Generally speaking, in India it is 

 advisable to use water of 50° to 55°, for throughout this period the eggs 

 are extremely delicate, and Indian operators are not as a rule capable of 

 sustained attention to detail, so that the period should be shortened so far 

 as is consistent with healthy development. 50° may be taken as the most 

 favourable temperature for " eyeing." Once the eyespots have appeared 

 the eggs are quite hardy and can be moved without danger. 



{iii) Planting Eyed Ova. — The eggs can now be allowed to hatch out 

 either in the natural Nurseries which it is intended to stock, or in the 

 Hatchery. For the former method it is impossible to improve on Mr. 

 Mitchell's " Pahdri " Hatching Box (Fig. iii), a sketch of which is attached. 



fPlanking 



paherj/r^or- * 



^ -«£inc 



The eggs are packed in boxes on trays protected by moss, and covered with 

 snow, and carried out to the springs. Tnere tliey are transferred into 

 pahdri boxes about 2,000 to a box — covered with a lid to exclude the light, 

 and left to hatch out. At a temperature of 50 the alevins will all be 

 hatched out in 47 days : thirty days later the fish will begin to feed on the 

 minute entomostraca in the water ; the holes at the top end of the box are 



