Table 2.

The morphological observations on the embryos of T. gratilla treated with FSW, highest nongametotoxic concentration of CdCl₂ and ZnSO₄ during 3 h, 6 h, 9 h, 12 h, and 24 h.

Time of observation		Treatments
	FSW (filtered seawater)	Cadmium chloride (CdCl2)	Zinc sulphate (ZnSO4)
3 hrs
2-cell	SCD	SCD	SCD
4-cell	SCD	SCD	SCD
6 hrs
8-cell to 16-cell	SCD	SCD, DE, EPC	SCD, DE, EPC
9 hrs
32-cell to 64-cell	SCD	ESD, DE	ESD, DE
12 hrs
Blastula	SCD	NFD, DE	NFD, DE
24 hrs
Gastrula	SCD	NFD	NFD
2-arm echinopluteus	SCD	NFD	NFD
General observation	No abnormalities	Formation of apoptotic bodies, cell fragmentation	Blebbing and deformed embryos

EPC = embryos with pigmented cells, SCD = successful cell division, ESD = embryo stop dividing, NFD = no further development, and DE = deformed embryos.