■2 HATCHING CERATODUS OVA. 



with a few corn sacks. Into each bottle one egg was dropped. 

 Upon examination of the ova in a week's time almost every 

 one was noticed to be alive ; this is easily seen by observ- 

 ing the change in shape of the yelk from the round to pear 

 shape (see figure, b and c). In three weeks' time the little 

 fish had left their gelatinous envelopes. A bit of conferva 

 was then dropped into each bottle for food ; shortly after- 

 wards the little fish were noticed to have insinuated them- 

 selves in the conferva and even when the latter had floated 

 to the top, as occasionally occurred, the fish were able to 

 find it. The bottles were disturbed as little as possible 

 and the water was not changed nor added to, and at the 

 end of four weeks, although the water had diminished by 

 evaporation to less than half, it made no difference what- 

 ever. 



The little fish after a week's sojourn in the pickle 

 bottles were removed to glass cells of a half to a gallon of 

 water capacity, prepared with some clay at the bottom 

 a,nd conferva ; ten fish were put into each vessel. Some 

 of the jars were placed in a tub of water so as to keep them 

 cool. Some were left on the table and in these the fish 

 thrived equally well, but a time came when the whole 

 lot suddenly died one day, and it was thought from the 

 water getting too warm. Some fish were put into a wooden 

 tub, it was half a wine cask ; I had used it before as an 

 aquarium ; it was cleaned out and filled with river water 

 and some conferva and pieces of floating green water weed 

 put in ; no clay or sand ; it was so arranged that any 

 insect enemies might be easily detected ; it was partly 

 covered over with a board to exclude light. The tub was 

 placed inside a galvanised iron wash tub containing water, 

 the idea being to prevent evaporation from the Avood. 



The fish for the most part lie quietly at the bottom ; 

 they never bury themselves in the clay and never come 

 to the top to breathe air. At night time they are more 

 active ; in one glass jar, which was totally immersed in 

 a tub of Avater, the little fish escaped into the tub during 

 the night. 



Xo attempt was made to feed the fish otherwise than 

 with conferva. There is evidently some other food neces- 



