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Skinner, Ernest B. (ed.) / Transactions of the Wisconsin Academy of Sciences, Arts and Letters
volume XIV, Part I (1902)

Marshall, W. S.
Entocythere cambaria (nov. gen. et nov. spec.), a parasitic Ostracod,   pp. [117]-Plate XIII ff.


Page [117]


  ENTOCYTHERE CAMBARIA (nov. gen. et nov. spec.),
               A PARASITIC OSTRACOD.
                    BY WM. S. MARSHALL,
         Assistant Professor of Zoology. University of Wisconsin.
  While examining a number of branchiae taken from recently
killed crayfish, I noticed on one of them a small crustacean,
which upon examination with a microscope', proved to be an
Ostracod. The peculiarity of its habitat at once struck me as
anomalous, and desiring to procure more specimens, I adopted
the following method which I found very satisfactory. When
any specimens of the Ostracod were wanted a crayfish was
killed, the branchiae removed and placed in a large watch-glass
partially filled with water. The Contents of this glass being
examined a few minutes later, the Ostracods, if present, were
found near the edge of the water at the side farthest from the
light, to which they appear very sensitive. As soon as the
branchiae were placed in the water the parasites would leave
themN and reaching the glass would crawl along it until they
came to the edge of the water, where they would remain as far
from the source of light as possible.
   The first crayfish (different species of Cainbarus) examined
were from, the vicinity of [adison; of these, nearly half were
infected. Other cravfish were obtained through a dealer and
varied considerably in their infection; some localities yielding
nearly as high a percentage as those near Madison, while cray-
fish from other localities appeared to be entirely free. The
dealer obtained this material from different parts of Wiscon-
sin, but I could get no definite locality other than Madison. At
no season of the year were the parasites entirely absent although


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