102 THE OCEAN 



different conditions. While the dredge may 

 be used on almost any kind of bottom and 

 scoops up the mud, sand and any slow-moving 

 creatures which are in its track, ^he trawl is 

 used only on comparatively smooth bottoms 

 and does not scrape up the mud, but merely 

 catches living creatures, plants and other 

 forms of life with which it comes in con- 

 tact. 



In addition to the trawl and dredge another 

 very useful piece of apparatus is used which 

 is known as the ^'Tangles" (Fig. 3). This is 

 simply an iron bar with rollers or runners on 

 the ends, and to it are attached a num- 

 ber of chains covered with masses of unrav- 

 elled rope. When the tangles are drawn over 

 the bottom the strands of rope become en- 

 tangled in the spines, branches or legs of va- 

 rious creatures and hold them fast and by this 

 simple method vast numbers of strange forms 

 of life are obtained which would escape both 

 the trawl and dredge. 



While these three instruments bring up in- 

 credible numbers of deep-sea denizens, yet the 

 spots which they actually touch and the locali- 



