51 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



On September 10th, a hundred quahaugs were planted in a box 

 whose bottom was covered with sand. The free edges of the 

 valves had been notched so that their subsequent growth could be 

 determined at any time by measuring from the notch to the edge 

 of the shell. Specimens taken from this box on October 16th, or 

 thirty-six days after planting, showed an average growth of 2.0 

 mm. (from the hinge to the edge). This would mean a weekly 

 average growth of 0.4 mm. The box was placed at about half-tide 

 level on the south shore of Mill Cove. 



On October 16th, four hundred quahaugs were planted in the 

 soil at low tide level on the south shore of Mill Cove, and directly 

 down from the box planted on September 10th. These quahaugs 

 have been living under conditions that are as natural as could be 

 given them. They are in the same soil from which they were 

 taken, and have a limited area (about five feet square) over which 

 they can move. Covering them, protecting them from enemies, 

 and confining them to the space to which they were transferred is 

 an inverted box, whose sides have been driven into the mud and 

 whose wooden bottom (which is now the top) has been replaced 

 I »y a wire screen. On January 19th, 1903, specimens taken from this 

 colony showed a growth that in the dorso-ventral direction aver- 

 aged only 1.0 mm. This indicates a slow growth as compared with 

 that of the clams planted in the sand bar on September 10th. 

 The latter had grown 2.5 mm. since October 16. 



This marked difference in the rate of growth of quahaugs dur- 

 ing the same period may be due to several causes, such as their 

 position with reference to the depth of water and the character of 

 the soil in which they were planted. Further experiments are now 

 in progress which have particular reference to the influence of soil 

 upon the rate of growth. If this factor is potent in determining 

 the growth, the fact is of considerable importance from the eco- 

 n ic point of view. 



