Abstract
The diploid chromosome numbers and karyotypes of Pracambarus clarkii and Nephrops japonicus are described by an air-drying method. The diploid chromosome number of P. clarkii is one hundred and eighty-eight (2n=188) in both the male and the female, among which forty-two meta- and submetacentric and fifty-two subtelo- and acrocentric pairs are included. The diploid chromosome number of N. japonicus is one hundred and thirty-six (2n=136) in both the male and the female, among which forty-six meta- and submetacentric and twenty-two subtelo- and acrocentric pairs are included. One subtelocentric pair of N. japonicus is remarkably large as compared with other pairs. The large chromosome pair is not found in P. clakii.
