44 THE PROBLEMS OF THE DEEP SEA n 



off the coral, which is brought up entangled in the 

 cords. A similar contrivance has arisen out of the 

 necessities of deep-sea exploration. / 



In the course of the dredging of the Porcupine, 

 it was frequently found that, while few objects of 

 interest were brought up within the dredge, many 

 living creatures came up sticking to the outside of 

 the dredge-bag, and even to the first few fathoms 

 of the dredge-rope. The mouth of the dredge 

 doubtless rapidly filled with mud, and thus the 

 things it should have brought up were shut out. 

 To remedy this inconvenience Captain Calver 

 devised an arrangement not unlike that employed 

 by the coral-fishers. He fastened half a dozen 

 swabs, such as are used for drying decks, to the 

 dredge. A swab is something like what a birch- 

 broom would be if its twigs were made of long, 

 coarse, hempen yarns. These dragged along after 

 the dredge over the surface of the mud, and en- 

 tangled the creatures living there multitudes of 

 which, twisted up in the strands of the swabs, 

 were brought to the surface with the dredge. A 

 further improvement was made by attaching a 

 long iron bar to the bottom of the dredge bag, and 

 fastening large bunches of teased-out hemp to the 

 end of this bar. These " tangles " bring up 

 immense quantities of such animals as have long 

 arms, or spines, or prominences which readily 

 become caught in the hemp, but they are very- 

 destructive tc the fragile organisms which they 



