42S 



MANUAL or THE MOLLUSC A. 



queutly found in the lobster-pots at Bognor, Sussex, which they enter to feed 

 \\\)0\\ the bait. 



JDredffhiff.— The Dredges used in the Oyster and Whelk-fisheries are so 

 rudely made as to injure the more delicate marine tmimals, and suffer all the 

 minute things to escape. It is therefore necessary to have instruments 

 specially adapted for the naturalist's work. 



Fig. 228. 



Plan of the Framework of a Dredge, reduced to ^. 



Fig. 228 is a plan, and Fig. 229 a side-view, 

 of a small dredge, belonging to Mr. J. S. Bower- 

 bank, and suited for such work as a private col- 

 lector might do on the English coast. It is made 

 of wrought iron, with moveable joints, so as to 

 fold up and carry in the hand. The bag attached 

 to the dredge is formed of two pieces of raw hide 

 {h, h), connected at the ends and bottom by net 

 {n) made of cod-line, to allow the water to escape; 

 and is fastened to the frame with copper-wire, 

 through the eyelet holes. The towing rope is 

 attached to the rings (r, r), and when thrown 

 overboard it scrapes with one or other of the 

 cutting edges {e, e'). The opening is made narrow 

 to prevent the admission of large and heavy stones. 



Dredging should not be attempted in a roinng- 

 boaf, unless near shore, in smooth water, and with 

 a depth not exceeding 5 or 10 fathoms. It may 

 be managed in a light boat by two persons ; one 

 rowing, the other holding the rope of the dredge 

 which is passed overboard near the stern.* 



* " Weymouth is pre-eminently thebest place on the 

 British coast for dredging. I can reckon 195 marine 

 species of shells that I have collected within a range of 

 five miles, and ten more species maj' safely be added. 

 Th; dredging is also easy and safe. The cost of a suit- 

 able boat and man is about 7s.6d. a day, i. e. from 10 or 



Fig. 229. 



