Abstract
Trematoda, which belong to platyhelminthes resemble many living organisms which have the ability to produce mineral concentrations and constitute as so called calcareous corpuscles, which were investigated in the present study in F, Gigantica, using Von Kossa technique. Results revealed the existence of calcareous corpuscles which were abundantly distributed in the potential organs with high metabolic functions like excretory, digestive and reproductive system, as well as the parenchyma. Whereas, they appear less abundante in the ventral sucker. On the ather hand the skin lacks the corpuscles, as the results of the present study, clear the aim of its performance to explain the centralize location, biological importance and the functional role of these corpuscles, leading to an increase in the limited available informational background for investigation on separation and distribution of the calcareous corpuscles and their roles which interact with its variable metabolic activities adult worm F.gigantica. The present work may be considered first in Ninevah province north of Iraq.