92 PRELIMINARY EXPERIMENTS ON 



Jar J was larger than the other two, and measured 18 inches long by 

 12 inches wide and 6 inches deep. This was immersed side by side 

 with jars D and F in one of the table tanks of the aquarium. 



Jars K and L were identical in shape and size, and measured 12 

 by 8 by 4 inches. They were immersed in the same tank as jar H 

 in front of a south window. 



One-quarter of the water was changed each day and fine plankton 

 was added each morning, as in the early days of experiments F and G. 



The early results of the experiments are shown in the table (p. 76). 

 Two of the losses recorded (one in J, and one in L) resulted from 

 accidents in changing the water, but from the second day of the 

 experiment it was obvious that the larvse were doing badly. A few 

 swam about a little in the early days, more particularly in J, but the 

 vast majority were very listless and inactive, making no efforts to feed, 

 and lying passively on the bottom of the jars or at the very surface of 

 the water immediately below the surface film. Their movements were 

 limited to occasional spasmodic jerks, contrasting markedly not only 

 with the movements of the larva? in the plunger-jars D, F, and G, at 

 a corresponding stage, but also with their own movements in the 

 plunger-jar in which they were hatched, previously to their transfer- 

 ence to the stagnant water. On the fifth day, when they were four 

 days old, their numbers were reduced to six, four, and seven respect- 

 ively ; and all, except one or two in J, were exceedingly torpid and 

 several in L were on the point of death. The experiments were con- 

 tinued a few days longer with no favourable change in the condition of 

 the larv?e and an increasing number of deaths ; but, as the results were 

 already conclusive, I soon afterwards abandoned the experiments as not 

 worthy of further attention. 



The behaviour of the larviii was precisely similar to that described 

 with such careful detail by Fabre-Domergue and Bietrix in their 

 admirable experiments upon Coitus and other forms, the principal 

 symptom of which was the progressive ana3mia and " etiolation " to 

 which the larvse in all their experiments fell victims. These naturalists 

 at first* attributed these results to the noxious influence of the water 

 in confinement, the precise nature of which was undetermined; but 

 in a later notet they account for the result as more probably due to the 

 failure to provide the larvae with the food most suitable to them at the 

 particular stage of growth. 



I quite agree with the French naturalists, as well as with Mr. Harald 

 Danuevig (loc. cit.), as to the necessity of supplying the larvae with suit- 



• Ann. Set. Nat., viii., 1897, pp. 212-17. 



t Role de la Vdsicule Vitelline dans la Nutrition larvaire des Poissons marins. Comptes 

 Rendus des Stances de la Societe de Biologic, 30th Avril, 1898. 



