1 12 
BULLETIN OE THE BUREAU OF FISHERIES. 
out apparent serious injury to the cyst. This condition is interesting, nothing like it 
having previously been noted in the parasitism of any of our mussels, so far as I know, 
and the causes leading up to it will bear careful investigation. This can be done only by 
a thorough study of the relations existing between host and parasite, in which connection 
it will be well to study in detail the structure of the gills of the host. 
Table III. — Number of Larval Q. ebena Carried by the Host. 
Species of fish. 
Date 
secured. 
Number 
of glo- 
chidia. 
Locality. 
Aug. 13,1912 
2, 100 
3»740 
I189S 
2, 700 
3, 200 
36s 
48 
26 
31 
9 
2.570 
Pearl Slough, Fairport, 
Do. 
Buttermilk Slough, Fairport. 
Upper end Geneva Island. 
New Boston, 111. 
La Crosse, Wis. 
Fairport, Iowa. 
New Boston, 111. 
Do. 
Genoa, Wis. 
Fairport, Iowa. 
Aug. 14,1912 
Aug. 17, 1912 
Aug. 26, 1912 
Sept. II, 1912 
Sept. 24, 1912 
Sept. 23,1912 
June 18,1910 
Monkey-face {Quadrula metanevra). 
During the early part of July five blue sunfish (Lepomis pailidus) and one green 
sunfish (A . cyanellus) were taken bearing a comparatively small number of glochidia of 
this mussel. The two heaviest infections are one of 50, the other of 69, and it is there- 
fore probable the sunfishes may be found to be the specific hosts of this mussel. By 
reference to figure 15 it will be found that one of the infections, taken July 2, is develop- 
ing, the adductors having become clearly defined and rudiments of the foot apparent. 
No change in form nor increase in size of shell is anticipated in this species. 
Table IV. — Number op Larval Q. metanevra Carried by the Host. 
Species of fish. 
Date 
secured. 
Number 
of glo- 
chidia. 
Locality. 
July 1,1912 
6 
Fairport, Iowa. 
July 2,1912 
50 
Do. 
do 
1 
Do. 
do 
6 
Do. 
do 
69 
Do. 
do 
IS 
Do. 
Blue-point ; Three-ridge {Quadrida plicata). 
The only fish so far taken infected with this species was on June 28, 1912, when a 
sauger (S. canadense) carrying 28 and a crappie (P. annularis) 4 glochidia were secured. 
The development is decidedly progressing as indicated in figure 16, where the foot and 
both adductor muscles are clearly defined. The figure (16) is a glochidium attached to 
edge of gill filament of the sauger. 
