Anie7'ican Fisheries Society. 99 



Such good results led us to follow iip this experiment with 

 others, working upon the same theory, namely that the water 

 should he constantly stirred. To do this a mechanical device has 

 been contrived which takes the place of the oar. 



This apparatus, which was put into operation at the begin- 

 ning of the present season at the floating lalioratory of the Ehode 

 Island Commission at Wickford, has proved to be very efficient 

 and a l)rief description of it may be of interest. 



Cylindrical cages, about five feet long and four feet in diame- 

 ter, made of fine meshed netting were used to contain the newly 

 hatched fry. On the inside of the cage near the l)ottoni was set 

 a two bladed propeller which could be rotated by a vertical shaft. 

 When the propeller was slowly rotated the water was forced 

 gently upwards and the fry, together with particles of food, were 

 kept constantly suspended. In oiir experiments twelve of these 

 apparatus were operated by a small gasoline engine. The pro- 

 pellers were kept constantly in motion day and night throughout 

 the season. When it was necessary to change the lobsters from 

 one cage to another or to put in a new experiment any of the 

 propellers could be easily thrown out of gear. 



The residts obtained by the use of this apparatus were cer- 

 tainly very gratifying to anyone who is at all acquainted ^\dth 

 previous experiments along this line. In order to ascertain 

 exactly what proportion of the fry could l)e reared, they were 

 carefully counted one by one at the beginning and at the end of 

 each experiment. From 1,000 to 5,000 of the newly hatched fry 

 were put into one cage and the percentage reared to tlie fourth 

 stage was in no case less than sixteen except in one case when the 

 bag was torn and the fry escaped. One experiment yielded 34 1-2 

 per cent., one 40 per cent., and one of the later experiments 59.6 

 per cent. 



Though a comparatively small numljer of experiments were 

 tried a total of 8,996 lobsters in the fourth stage were obtained. 

 These were placed in cages with sand or gravel bottoms for they 

 no longer needed attention when provided with a place to biir- 

 row or hide and enough to eat. 



A number of loljsters hatched last year were carried over win- 

 ter in similar sand cages and are now from one and one-half to 

 three and one-half inches in length. 



