290 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Thiu-shelled mussels are absolutely useless for buttou-makiug. Even if originally 
as thick as a button, the uecessary grinding and polishing reduce them to mere wafers. 
The preferred color is white, but cream colored shells are also employed. Shells with 
pink, purple, yellow, or salmon-colored nacre are not suitable, as the color fades with 
age and is apt to be not uniform. Certain shells that satisfactorily combine thickness 
and color are nevertheless useless, because they are soft or brittle and break easily 
during manufacture. Dead shells that have been exposed for a long time to the action 
of air or water also become useless for button-making. , 
Mr. Charles T. Simpson, of the department of mollusks of the United States 
National Museum, has courteously supplied the newly revised scientific names for the 
mussels used in the button industry, and has given valuable information concerning 
this family of mollusks, with which he is so familiar. For a very interesting and timely 
article on the fresh water mussels, considered from the standpoint of the biologist, 
reference is made to Mr. Simpson’s paper entitled “The pearly fresh-water mussels 
of the United States, their habits, enemies, and diseases, with suggestions for their 
protection,” published in the Bulletin of the U. S, Fish Commission for 1898, 
Coincident with the establishment of the mussel fishery and button industry in 
Iowa and Illinois, there has arisen a new popular nomenclature for the mussels or 
“clams” utilized. The names applied by the fishermen and manufacturers have some 
reference to the color or shape of the shells. Originall^^ cpiite local, they are now 
generally apjilied throughout the whole stretch of river in which fishing is done. 
The principal species of mussel iu the Mississippi River used iu button-making is 
(Jumdrula ehena, generally known as the “niggerhead.” This species has the general 
shape of a common round clam ( ^^enus mercenaria)^ and is characterized by a very 
thick and heavy shell, with a black or dark -brown outside skin and a glistening white 
interior, the latter color being uniform through the thickness of the shell. It is of 
relatively small size, the maximum being only I^- or 5 inches for the greatest outside 
diameter and the average about 3 inches. Many less than 2 inches wide are also 
unnecessarily destroyed. It is often found over immense areas, preferring muddy 
sand and muddy gravel bottom, but also frequenting sandy bottom. In some places 
a form of this mussel known as the “ mud niggerhead” is sparingly used. It is found 
on muddy bottom, and has a thicker shell and a more intensely black epidermis than 
the common form. 
Several abundant species of mussels resembling the niggerhead in shape, but 
differing from it in having tubercles or excrescences on the outside of the valves, are 
locally known as “warty-backs” or “warty-back niggerheads” [Qiiadrula pmtidosa; 
Q. metanevra). They have very little value for buttons, the warts causing the shell to 
crack during cutting. 
Another species of this class that is abundant, but only sparingly used, is the 
“bullhead” [Pleurohema (cso^ms). It is found with the “niggerhead,” has a thick 
shell with a blackish-brown skin and a white interior, and externally presents several 
radiating ridges. It is of little value, as the shell is brittle and cracks iu cutting, and 
the buttons also split in facing and drilling. 
There are several kinds of mussels known along the Mississippi as “sand shells.” 
The most abundant and important of these is the “yellow sand shell” or “yellow- 
back” {Lampsilis anodotitoides), which has a bright yellowish-brown epidermis and a 
faintly cream-colored interior. Another species with a black exterior is known as the 
“ black sand shell ” [Lampsilis rectus). The sand shells are found chielly on sandy 
