24 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



very credible and recalls the egg of Columbus. Besides it should 

 be remarked that the idea of employing mechanically stirred water 

 in an aquarium for artificial rearing has often, in recent times, been 

 turned to account. So, e. g., the "plunger jar" of C. T. Brown, first 

 used in England for raising medusce and other delicate organisms, in 

 which the motion of the water is produced by the raising and lower- 

 ing of a glass plate in the experiment jar, is constructed on a similar 

 idea (cf. Journ. Marine Biol. Assoc. Plymouth V, 1897-99, p. 176, 

 fig. 1;) and the apparatus of the Frenchman, Fabre Domergue and 

 E. Bietrix employed with great success in the raising of flatfish 

 larvse, especially soles (of. Developpement de la Sole, Paris, 1905, 

 Vuibert et Nony, Editeurs, p. 219 et seq., fig. 37-39) is really noth- 

 ing else than a — clearly independently constructed — repetition of 

 the Mead lobster-hatching apparatus on a small scale and for labor- 

 atory purposes, in which the gasoline machine is replaced by a \ HP 

 hot air motor and the large hatching bags of canvas by glass dishes 

 containing 12 liters, while in place of the propeller with its two blades 

 an upright, rotating glass plate is used with an inclination toward 

 the vertical axis of rotation.* 



These similarly directed efforts to find the proper ways and 

 means for the construction of apparatus for the artificial rearing of 

 delicate developmental marine forms strengthen the impression 

 that the right way has been entered upon, and the success al- 

 ready attained make it a certainty that the possible improvement 

 yet to be made can concern only accessories. To the last belongs 

 the not yet satisfactorily settled question concerning the proper 

 food for the young lobster larvae. Thus far finely minced clams, 

 and shredded fish have been employed but without establishing the 

 conviction that this is the correct food. Also better means must 

 be found for keeping off disturbing plant growths, especially diatoms, 

 which are only moderately kept down by shading the hatching 

 bags. The keeping up of a proper temperature, not too low, as 



* An apparatus of this kind is now employed in Helgoland for experiments in lobster 

 raising. 



