150 



SCIENCE 



[Vol. IV/, No. 81. 



use of a greatly modified form, called the rake- 

 dredge, the object of which is to dig deeply into 



Fig 



Verrill's rake -dredge 



frame is reversible in use, working either side 

 down. It is also so bolted together that it 

 can be folded up for convenience in trans- 

 portation. From a crossbar near the hinder 

 end of the frame, there is suspended a capacious 

 net, which trails behind. The mouth-frame of 

 this net is made of round iron. 



This implement, therefore, consists essential- 

 ly of a large dredge, not famished with scrapers, 

 but preceded by a stout rake or harrow. The 

 character of the work which it is intended to 

 perform is obvious, and the many interesting 

 forms which it has added to the collections of 

 the fish-commission have caused it to be con- 

 sidered one of the most important additions to 

 the dredger's outfit. It can, however, be used 

 only on smooth muddy or sandy bottoms, and 

 requires considerable force to drag it through 

 compact mud or sand. 



The same form of rake-dredge, without alter- 

 ation or improvement, was adopted by the 

 French exploring-steamer Talisman in 1883. 



Capt. H. C. Chester of the fish-commission 

 party devised, in 1880, a new form of rake- 

 dredge (fig. 9), which is now generally em- 

 ployed in place of the old pattern. The net is 

 similar to the one above described ; but the rake 

 consists of a heav} T rectangular frame of flat 

 iron, along the opposite and longer sides of 

 which the teeth are arranged, projecting out- 

 wards. The rake-frame measures three feet 

 long by nine inches wide ; and the teeth are 

 about eight inches long, stout, curved, and 

 pointed. 



The principal improvement claimed consists 

 in separating the two rows of teeth so that the 

 upper row ma} 7 not interfere with passage back- 

 ward into the net of the larger objects dug up 

 by the lower teeth as they scrape along the 

 bottom. 



the bottom, and unearth the many burrowing 

 forms of marine invertebrates which are rarely 

 taken in the old pattern. 



This apparatus consists 

 of a triangular frame of flat- 

 bar iron, each side meas- 

 uring forty-two inches in 

 length. The hinder por- 

 tion of the frame, which is 

 three feet long, is constructed of two bars 

 placed face to face, each furnished with six 

 strong iron or steel teeth, about a foot in 

 length, on opposite sides. These teeth, there- 

 fore, project in opposite directions ; and the 



RAKE-DREDGE. 



An ingenious pattern of rake-dredge, in- 

 tended for collecting small forms of inverte- 

 brates in shallow water, was invented in 1880 

 by Mr. James E. Benedict of the same party. 

 As represented in fig. 10, it consists of a double 



