32 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



drawn in through the incurrent openings of the snout or siphon. 

 The food consists of microscopic organisms of various sorts, a 

 large portion being diatoms. The abundance of this food varies 

 in different localities, and in the different depths of water, and at 

 various times of the year. The clam feeds continuously when 

 covered with water, if it is comfortably situated.* 



The work of the past season, 1902, may be conveniently classi - 

 fied under the following headings : Further observations on the 

 breeding season, spat collecting apparatus, continued growth of 

 " artificial set," continued experiments in transplanting clams upon 

 reserved plots, and enemies of the clam. 



Further Observations on the Breeding Season. — The possibility 

 that there is a second more or less extensive breeding season for 

 the clam, in certain years at least, is indicated by the observa- 

 tions made in the spring of 1900, and we quote the following para- 

 graph from the report of that year : 



" Between the regular spawning season of June, 1899, and June, 

 1900, there was another distinct breeding season, probably in the 

 fall of 1S99. The set resulting from this was first discovered in 

 April, 1900, when the largest specimens were about one-quarter 

 inch long. The evidence that this was a fall set is that every spec- 

 imen had the surface of the shell next to the hinge corroded and 

 distinctly marked off from the new growth. This condition is 

 never seen in the summer set, but would be accounted for if the 

 clams lay for months with almost no growth. The mark persists in 

 these specimens until they are more than an inch long. By the 

 tenth of June some of these had grown to 30 mm. in length and 

 were as Long as many sexually mature year-old specimens. Pho- 

 tographsof specimens taken May, 1900, are shown in figure 7." 



In the spring of 1001 very few clams were observed which 

 seemed to have set out of the regular season, but during the pres- 

 ent winter such specimens ha\e been found in greater numbers 

 than ever before. In the latter part of January, 1903, small clams, 



ior1 for L901 pp. »0 



