300 TRAWLING. 



nacles are seated by thousands on its surface. Most 

 of tlie burrowing Bivalves, however, are to be dug 

 out of the sand or mud of the flat shore, and many- 

 interesting animals are found on the beds of sea-grass 

 [Zostera) that grow on such a coast. These are col- 

 lected by means of a keer-drag, a form of net which 

 I have described, with the mode of using it, at 

 p. 49, ante. 



Dredging. — In the previous pages I have also 

 given a full description of dredging and its prolific 

 results, whereby the bottom of the deep sea is scraped 

 and the varied contents brought to light. Multitudes 

 of animals of the highest interest are procured by 

 dredging that the shore-collector would never find ; 

 and yet shore-collecting must always be the main 

 resource, at least of the majority. 



Trawling. — Though this is a mode of fishing too 

 cumbrous and expensive for the amatem' generally, 

 the naturalist may occasionally benefit by its wide- 

 sweeping action. I have described it in my " Tenby," 

 pp. 185—198. 



Mr. Dempster, of Edinburgh, has recently invented 

 an ingenious improvement on the old trawl, analogous 

 to that which distinguishes the naturalist's from the 

 common oyster-dredge. 



The ground-rope is dispensed with ; a rod of cast- 

 iron passing across from the heads both above and 

 below the mouth of the net, so that the net is sure to 

 be right, however it fall. The beam is moveable, 

 rising to the edge that happens to be uppermost by 

 its own lightness, while a curtain that stretches 

 from it to another beam in front, to which the bridle 



