NATURAL HOSTS OF FRESH-WATER MUSSELS. 
107 
Yellow Sand-shell {Lampsilis anodontoides). 
During the latter part of June and early in July this mussel was found on the two 
species of crappie and on Apomotis cyanellus and Lepomis humilis, but in such limited 
numbers that it is extremely doubtful if any of these fish are the actual host, as the 
greatest number occurring on any one species was six. As this time is the height of 
the spawning season of this particular mussel, and all the infections were recent, it is 
presumed they were more or less accidental. 
Some sunfish infected artificially with glochidia of this mussel July i, 1911, appar- 
ently took well and were deeply encysted at the end of three and three-fourths hours, 
but two days later not a single glochidium could be found on any of the fish, due proba- 
bly to unfavorable conditions. On June 27, 1910, a lot of fish, chiefly Pomoxis and 
Lepomis, with a few Micropterus, Aplodinotus, and Roccus were infected and apparently 
took well, but the glochidia never completed their metamorphosis. However, on August 
II, 1910, a few metamorphosed on a sunfish {A . cyanelhis) in four days, about i per cent 
of those enc3'Sted. 
Slough Sand-shell {Lampsilis jallaciosa). 
On June 27 a crappie (P. anmdaris) was taken holding 16 glochidia of this species, 
but it was not again found till October 15, when a sturgeon (S. platorhynchus) was 
taken holding 125. On November 7 another sturgeon was taken holding 56. 
This glochidium does not, as a rule, take very near the tips of the filaments in the 
sturgeon, but rather deep, a great many as deep as the fork of the filament, and encyst- 
ment is very heavy. The October infection indicates but very slight development, 
or none at all; cysts enormous. Examination of the November infection reveals the 
fact that the adductor muscle is dividing and traces of the foot are clearly discernible. 
It is believed these sturgeon become infected sometime during September or October, 
and the metamorphosis would, therefore, not be completed till some time during the 
following spring. 
Higgins Sand-shell {Lampsilis higginsi). 
The only fish so far taken which unquestionably holds this glochidium is a specimen 
of Stizostedion canadense taken October 4, 1912; it holds approximately 600 glochidia. 
The infection was recent and no development is clearlj^ indicated; cysts very heavy. 
Paper-shell {Lampsilis Icevissima). 
For the past three years we have been taking sheepshead {Aplodinotus grunniens) 
bearing enormous numbers of young Icevissima, generally in a high state of development. 
The sheepshead, from its habits, should be expected to be found more frequently infected 
than most any other species of fish, yet the percentage of infected fish is small. 
Only 2 per cent of the fish taken during the period from June to November were 
infected with this lanm, the number carried by each fish varying from 112 to 850. It 
was hoped that a critical study of the material would indicate the period of parasitism, 
but such is not the case, though I am of opinion that it covers a period of nearly a year. 
