[85] U. S. P^ISH COMMISSION STEAMflR ALBATROSS. 87 



MUD BAG. 



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

 the uet removed and the rear end of the cauvas shield closed, makiug a 

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

 tiud it filled with a compact mass of mud or ooze wheu 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 in the specimen cup. 



IMPROVED BEAM TRAWL. 



This trawl, Plate XL VIII, was introduced by the writer in 1884* and 

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

 the one shown in Plate XLVII. 



NOMENCLATURE. 



a. Beam, iron pipe. 

 h. Runners. 



c. Trawl net. 



d. Pocket. 



e. Jacket. 

 /. Bridle. 

 g. Shackle. 

 /(. Lashinga. 

 ('. Mud bag. 

 ;'. Lead rope. 



/.-. Arms, wood. 

 /. Wing nets. 

 m. Guard nets. 

 n. Dredge rope. 

 0. 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, t% inch. 

 Collars : 



Brass, width, 'd^ inches. 



Thickness, f inch. 



Length, 9^ inches. 

 Bolts: 



Iron, round, diameter, finch. 



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

 Runners : 



Iron, flat-bar, length, 5 feet. 



Height, 2 feet 5 inches. 



Height, including collars, 2 feet 9 inches. 



Width, 3^ inches. 



Thickness of metal, ^ inch. 



* Owing to dela,y in printing we are able to introduce this and other late improre- 

 ments into this report, 



