The specimens collected 1week prior to sex
differentiation without the gonopore complexes devel-oped a thoracic spine between the fifth walking legs
(Fig. 1A) first visible when it was approximately 7days
of the postlarval stage. They all showed undifferentiated
gonad which appeared as a cluster of germ cells (Fig.
2A) located between the heart and hepatopancreas (Fig.2B).