APPENDIX. 



ON THE FERTILIZATION AND TRANSMISSION OF LIVING 

 PELAGIC (floating) AND OTHER EGGS OF BONY FISHES. 



Though living adult fishes should always be chosen for the 

 supply of eggs and milt, yet satisfactory results can be obtained 

 from those which have been dead for some time. The collector 

 therefore need not despair of recently dead fishes. By gentle 

 pressure along the belly in tlie direction of the vent the transparent 

 ripe eggs readily escape into a vessel of clean sea-water. If too 

 much pressure be applied, unripe eggs, which are easily recognized 

 by their opacity, are extruded, and they at once go to the bottom 

 of the vessel. In the same way the milt of the male (a whitish 

 creamy fluid) is gently squeezed out, and a very little allowed to 

 drop into the vessel of sea-water amongst the eggs. Care should be 

 taken not to add too much milt, as it renders the water impure 

 during a journey, and thus causes the death of the eggs at an early 

 stage. It is surprising to find how little milt will sufiice to fertilize 

 thousands of eggs in a large vessel. 



Living eggs are at once distinguished from dead eggs by their 

 buoyancy and glassy translucency. Unhealthy eggs become slightly 

 milky and then wholly opaque. No reliance can be placed on 

 eggs showing the faintest trace of this condition. 



A few minutes may be allowed to elapse before measures 

 are taken for renewing the sea-water and removing debris and 

 dead eggs, meanwhile the vessel should remain at rest. If 

 the eggs are very buoyant they may be collected at the surface 

 with a shallow scoop of horse-hair or any similar instrument — 

 such as a large spoon, a hand-net or a saucer, and placed in perfectly 



M. F. 30 



