[85] U. S. FISH COMMISSION STEAMER ALBATROSS. 87 



MUD BAG. 



The mud bag used by us with the trawl is simply a boat dredge with 

 the net removed and the rear end of the canvas shield closed, making a 

 water-tight bag. We lash this to the tail of the trawl net and usually 

 iind it filled with a compact mass of mud or ooze when it comes up. 

 This affords many interesting specimens besides enabling us to deter- 

 mine the character of the bottom more accurately than we could by ex- 

 amining the small amount brought up iu the specimen cup. 



IMPROVED BEAM TRAWL. 



This trawl, Plate XL VIII, was introduced by the writer in J 884* and 

 is the latest form used on board the Albatross. It is a modification of 

 the oue shown in Plate XLVII. 



NOMENCLATURE. 



a. Beam, iron pipe. 



b. Runners. 



c. Trawl net. 



d. Pocket. 



e. Jacket. 

 /. Bridie. 

 g. Shackle. 

 h. Lashings. 

 i. Mud bag. 

 j. Lead rope. 

 k. Arms, wood. 

 I. Wing nets. 

 m. Guard nets. 

 n . Dredge rope. 



o. Dredging block. 



p. Dredging boom. 



q. Bridle stops. 



r. Collars, brass. 



DIMENSIONS. 



Beam : 



Iron pipe, length, 11 feet. 



Outside diameter, 2$ inches. 



Thickness of metal, -rV inch. 

 Collars : 



Brass, width, 3J inches. 



Thickness, f inch. 



Length, 9| inches. 

 Bolts: 



Iron, round, diameter, £ inch. 



Set screws, in collars, iron, square heads, diameter, J inch. 

 Runners : 



Iron, flat-bar, length, 5 feet. 



Height, 2 feet 5 inches. 



Height, including collars, 2 feet 9 inches. 



Width, 3i inches. 



Thickness of metal, | inr.k. 



* Owing to delay in printing we are able to introduce this and other late improve- 

 ments into this report. 



