A NEW PRINCIPLE OF AQUICULTURE. 773 



Emmel in rearing fourth-stage lobsters to the fifth stage." Ninety fourth-stage 

 lobsters were put separately into glass jars, one lobster into each jar, and the 

 whole crate of jars submerged in the water about 2 feet below the surface. A 

 screen of woven copper wire was placed over the wide mouth of each jar to keep 

 the lobsters from escaping. All these lobsters were found dead twelve hours 

 later. Galvanized copper wire screen was then substituted in a new experiment 

 and in twenty-four hours the whole lot were dead. Finally a cloth screen of 

 bobbinet was used, and out of 75 lobsters which were fed, only i died before 

 moulting into the fifth stage. Of 15 which were not fed 4 died at the end 

 of a month. These difficulties, if recognized, may in most cases easily be 



overcome. 



TESTS OF EFFICIENCY. 



The method and apparatus which have been herein described have been 

 developed, as we have said, mainly in connection with the rearing of lobsters 

 through their pelagic larval stages. But as proficiency in this work has increased 

 we have come to realize that the method is equally well adapted to the rearing 

 of a great variety of fishes and aquatic invertebrates. 



Hatching and rearing lobsters. — While the hatching of lobster eggs by this 

 method presents no difficulties, and young lobsterlings, after reaching the fourth 

 stage, can also be cared for without the use of special appliances, the larval 

 lobsters, on the other hand, during the three free swimming stages of two or 

 three weeks' duration, seem to incarnate nearly all the perverse and intractable 

 characteristics which, from the view point of fish culture, are difficult to deal 

 with. They are pelagic and are safe only when floating, yet in confinement 

 they persistently tend to go to the sides and bottom of the inclosure. They 

 are comparatively slow of movement and weak in their instincts of self-preser- 

 vation and of seeking food, yet their most distressing characteristic is canni- 

 balism. A method of artificial culture, therefore, which will successfully cope 

 with the various difficulties involved in the rearing of larval lobsters might, a 

 priori, be expected to answer the requirements of the culture of fishes, few of 

 which, perhaps, offer so many difficulties. While the report on the special 

 method of rearing lobsters is given in another paper, it may here be said, as 

 indicating the general efficiency of the plant, that during the months of June 

 and July and the first few days in August of this year we hatched and reared 

 through their successive larval stages more than 320,000 lobsters (counted) by 

 means of the apparatus as above described. 



Fishes incidentally reared. — While the apparatus was occupied with the 

 rearing of lobsters, time and car space were not available for experiments on the 

 rearing of fishes, but incidentally it was demonstrated that the young of many 

 fishes would thrive and grow in the cars. Upon raising cars which had been 



"Report of Rhode Island Commissioners of Inland Fisheries for 1907, p. 104. 



