56 BULLETIN OF THE BUREAU OF FISHERIES. 
It is well to point out that the meshes of the net should be of such a size as to per- 
mit the small shells to pass through and remain at the bottom. Some small mussels 
will undoubtedly be held in the net by the mud and larger shells, but these can be culled 
out readily and returned to the water without any material injury. 
It may be noted that occasionally some of the thinner-shelled mussels, such as the 
floater, paper-shell, etc., are pierced by the teeth of the dip net, which, of course, kills 
the mussel. These shells, however, are not now of any commercial value. 
SHOULDER RAKE. 
The shoulder rake can be used to advantage in comparatively swift water, espe- 
cially when the bottom is not too hard and is free from hang-ups such as rocks and 
sunken logs. The implement consists of a metal rake about 1 foot long and provided 
with 10 to 12 coarse teeth or curved tines, which may be about 9 inches long (Pl. XXIX, 
fig. 2). The rake is securely bolted to a wooden handle 15 to 20 feet long, its length 
being adapted to the depth of water. A basket, made of poultry-wire netting, is 
attached to the rake and handle in such a way as to afford a concave receptacle for 
the shells. A small board, about 10 inches by 2 feet, is usually fastened to the handle 
approximately 1 yard from the base. The method of operation is rather simple, 
though laborious. The boat in which the work is carried on is anchored over the 
mussel bed, and the rake is placed into the river at the head of the boat and slowly 
worked down to the stern, when it is raised to the surface. The shells are thrown into 
the boat. The board attached to the handle offers resistance to the current, and 
thus is of considerable assistance in raising the rake, as well as in driving it down- 
stream over the bed; it therefore has the same function of an underwater sail as the 
mule used in crowfooting, but the power of the current acts only upon the rake, 
and not upon the boat. The shoulder rake may be made from a coke fork. The tines 
are ctit to the desired length, heated, and bent at right angles to the handle. A Jong 
handle must, of course, be substituted for the short handle of the coke fork. 
The results of this method are generally satisfactory, if the shells are relatively 
abundant. Small shells inadvertently taken can be thrown back with assurance, 
generally, that they will live. 
The shoulder rake is a common implement on the Mississippi River and other 
streams. On the St. Francis River, Ark., it is the principal method employed in the 
summer and fall, while the crowfoot is chiefly used in the high water of spring. The 
fork, to be described later, is also used in very low water. 
SHELL TONGS. 
The shell tongs, or scissor forks, are used to some extent on the upper Mississippi, 
the Cumberland, the White, and some other rivers where the work can be carried on 
satisfactorily in rather deep water. It is possible, of course, to work between the free 
spaces of a series of logs or other obstructions. It is essentially a grapple, consisting 
of two rakes, or forks, on the ends of long handles which are pivoted together about 2 
feet from the lower end, after the fashion of a pair of scissors (Pl. XXIX, figs. 1, 2, 
and 3). ‘The method of its operation is similar to that of the oyster tongs; the appli- 
ance is lowered into the water from an anchored boat, then by bearing down on the 
