125 



applied also to other ^enera nf marine Lamellibranrlis, 

 both round our own coasts and in America. 



The condition most favourable for the formation of 

 a Pecten bed is a shelly bottom, with a little mud. Too 

 much fine mud is detrimental. The most favourable 

 depths are from five to twenty fathoms, thoup-h the species 

 occurs sporadically in much deeper water, but not in 

 communities. The animal seems to be readily injured by 

 a low temperature, and in the year 1895 large numbers 

 w^ere killed in the Firth of Forth by the long continued 

 cold weather. 



Scallop dredging extends almost throughout the 

 year in the Firth of Forth, but very little goes on during 

 the time of the herring fishing in summer, and this is the 

 time when the shellfish are least valuable, for owing to 

 their gaping shells and their habit of clapping the valves 

 the sea water cannot be enclosed, as in the mussel or 

 oyster, and the animal, consequently, soon dies when 

 removed from the water. 



The dredge used for the purpose of clam fishing is an 

 oyster dredge of five to six feet in breadth of mouth. The 

 net attached to the frame is made up, on the lower side, 

 of a series of iron rings laced together with short pieces 

 of wire, so> that repairs can be very easily made with 

 additional rings and wire. The upper side of the net is 

 composed of ordinary twine. The clams are mostly used 

 for the baiting of long lines, five hundred clams being 

 required for a line of one thousand hooks. 



With regard to the value of cla,m as bait, experiments 

 have been carried out by the Scottish Fishery Board, 

 from whose reports the figures given have been taken. 

 The lugworm (Arenicola) seems to have given the best 

 results, though the mussel {Mytilus) and clam (Pecten) 

 come close after, and the three are probably about equally 



