The karyotypes of loach Misgurus anguilicaudatus, zebra fish Brachydaniorerio, oyster Crassostrea gigas and hard clam Meretrix lusoria were obtainedusing embryo chopping method.
The diploid chromosome numbers of each species are as follows, (a) loach:48, including 2 pairs of metacentric, 8 pairs of sub-metacentric, 1 pair ofsubtelocentric, and the other 13 pairs are telocentric chromosomes; (b) zebrafish: 48, including 3 pairs of metacentric, 17 pairs of submetacentric, 4 pairsof subtelocentric ones; (c) oyster: 20, including 10 pairs of metacentric ones;(d) hard clam: 50, including 10 pairs of metacentric, 14 pairs of submetacentricand 1 pair of subtelocentric ones.