Cell within a cell or a circulating cell pair

@article{Dybas1975CellWA,
  title={Cell within a cell or a circulating cell pair},
  author={Linda K Dybas},
  journal={Nature},
  year={1975},
  volume={257},
  pages={790-791}
}
I WISH to report that one of the coelomocytes of Phascolosoma agassizii Keferstein, 18661 (collected from Arroyo de Frijoles State Beach, California) which was previously considered to be one granulocyte is seen, under the electron microscope, to consist of two separate cells in a unique relationship.