Feeding: 



The larvae of each rcarin^^ group have been nourished with a 

 beef liver puree; sone tines \re have served a puree of the nuscles 

 of the soft-shelled clam in place of beef liver. This puree of 

 beef liver was prepared by passing the frozen, liver through r. neat 

 grinder. This nourishment is used in similar establishments because 

 it is relatively cheap and it is easy to obtain all the timeo The 

 feeding of the larvae at the Biological Station has necessitated the 

 purchase of 170 legs. (340 livres) of beef liver. The food vras dis- 

 pensed at the rate of one teaspoon of puree diluted in 200 co. of 

 sea vrater per 3000 larvae every tv/o hourso 



V'Je have often observed that excess food^ which stayed sometime 

 on the bottom of the rearing tanks, vrs harmful* The larvae agglu- 

 tinated themselves occasionally with the v;aste food and diedi« This 

 act occurs especially in the oval basins where the Virr.ter circulation 

 differs fVc-m that of the other tanltso Ccnoerning the toxicity of the 

 liver particles remaining some hours v/ith the larvae, (we) mention 

 the folloY/ing experiment : larvae placed individi^ally in 250 cc. 

 beakers died if the particles of beef liver remr-.ined in the beaker 

 more than tv/o or three liours; on the contrary^, larvae of the sane 

 age, receiving no food, stayed alive well durin:; several days and 

 the sane were able to survive if, after this fasting, they v/ere fed 

 again. 



The too prolonged stay of the excess food in the tank is woeful 

 for the survival of the larvae© This misfortune that occurs some 

 tines in the oval tanks may be xrcll due to the reasons: too slot/ 

 elimination of the excess food; circulation favoring the a^^glutinat- 

 ion of the excess food; insufficient supply of water* These three 

 reasons m.ore or less related to each other ];r.y be easily corrected* 



Moulting ; 



At temperatures of 18,0^ Ce the larvae nr.ike their first shedding 

 about the 5th day; their second moulting about the IQth day and the 

 third at the 14th dayo 



Experi-.icnts on the 4th sta ge larvae: 



IXaring the first fortnight of the mnth of September, 71 larvae 

 in the 4th stage have been isolated individually in 250 cc. beakers. 

 This experiment v/as for the ■lurpose of obtaining information oyi the 

 intermoult period betv/een the 4th and 5th stage* They have had the 

 ViTcter changed tiTice a day an'I fed oi\ly once a day. After the 10th 

 day of observation, one recovered: 



29 



