The distribution and relative abundance of Nematopsis spp., as found in Crassostrea virginica in (Gmelin) in the Galveston Bay area.

Nematopsis ostrearum and Nematopsis prytherchi were found in the tissues of Crassostrea virginica. A third species of unknown significance, was observed in small numbers. The two known species were found at each of the 16 sampling sites, the third species occurred at three locations. Of the 400 oysters studied, 99% were infected by N. ostrearum, 89% were infected by N. prytherchi, and 3% were infectd by N. sp. Wide differences in levels of infection were found in the samples. This was attributed to differences in proximity of host decapods and to seasonality. Infection experiments were conducted to confirm Eurypanopeus depressus and Panopeus herbstii as hosts of N. ostrearum, and Menippe mercenaria as a host of N. prytherchi.