44 INLAND FISHERIES. 



The weekly averag-e up to October 15tli was somewhat diminished, 

 being- 213 per cent. The size at this date is shown in Fig. 4. 



I may here once more refer to the effect of varying- conditions 

 on g-rowth, for the box was within a few feet of experiment 24 in 

 which the box had high sides (referred to above). But especially 

 I would call attention to the two smaller specimens in Fig. 3, which 

 are the same ag-e as the larger in the group, but were left on the 

 shore in the original box covered with a piece of wire gauze which 

 j)revented free circulation of water. 



Clams planted hi land-tiles. — In the middle of July, 1899, some 

 specimens of the set of the previous mouth were planted singly in 

 land-tiles which were set in the ground vertically, the specimens 

 measiiring from 12 to 15mm. On September 18, 1899, some of 

 them were measured, and the growth was found to have been re- 

 markable. The larger specimens then measured 46mm. One of 

 these, together with a small clam of 12mm. (to show the original 

 size in July), was photographed, and the figure is reproduced in 

 this report (Fig. 6). Some of the tiles were left undisturbed until 

 September 10, 1900, when three of these clams were found in them. 

 They measured 65, 74, and 78mm., or about three inches. The 

 largest was at the lowest level on the shore. One of these is 

 photographed in Fig. 7 ; it is a specimen known to be one year and 

 four months old. The surface of the shell was still covered with 

 the skin which is usually rubbed off, and there is no line of growth, 

 owing to the fact that the clam was not disturbed during its life 

 of more than a year in the tile. These specimens demonstrated 

 also as clearly as could be desired that it is necessary to dig up 

 the soil in order that the clams may thrive. 



