Table 2.

Cell morphotypes used in this study to classify total hemocyte populations in Styela plicata

Cell morphotype	Diameter (µm)	Percentage (%)	Possible types	Description
Small-round cells	2.8–6	16.7 ± 9.3	Lymphocyte-like cells, hemoblasts	Circular cells with a high nucleus/cytoplasm ratio. Granules scarce or absent
Granular amoeboid cells	4–8	9.9 ± 5.9	Granulocytes and amoeboid cells in differentiation	Amoeboid cytoplasm with granular contents
Large granulocytes	5–8.6	46.2 ± 9.9	Fully differentiated granulocytes, univacuolar refractile granulocytes	Rounded contour, numerous granular structures in cytoplasm, a large refractile vacuole may be present
Vacuolated cells	5–20	31.4 ± 8.8	Simple univacuolar cells, compartment cells, morula cells	Cells with one or more prominent basophilic vacuoles in the cytoplasm
Pigmented cell	8–13	3.5 ± 3.9	Pigment cell	Large cells, cytoplasm saturated with compartments filled with amber pigment