THE DEVELOPMENT OF THE EXCRETORY SYSTEM OF CLONORCHIS SINENSIS IN ITS DEFINITIVE HOST

The flame cell formula of Clonorchis sinensis remains unchanged during its cercaria and metacercaria stage, representing itself as 2× [ (3+3) + (3+3+3) ] (Komiya and Tajimi, 1940), while Metorchis orientalis, which belongs to the same Family as the former, increases the number of its flame cell during its metacercaria stage. The flame cell formula of its mature cercaria is considered to be 2× [ (6+6) + (6+6+6) ], but in its metacercaria stage, each tertiary collecting tube except the first one increases one to two flame cells irregularly, thus representing the formula as 2× [ (6+6+ (1-2) ) + (6+ (1-2) +6+ (1-2) +6+ (1-2) ) ] (Komiya and Tajimi, 1941) . When entered into its definitive host, the flame cell formula of Metorchis orientalis shows fundamentally no marked change from that of its metacercaria, at most several flame cells are added to each flame cell group of the tertiary excretory tube (Komiya and Tajimi, 1941) .The purpose of this work is to study the general aspect of the excretory system of Clonorchis sinensis after the entering its definitive host.