Additional Excretory organs:

1. Skin: Many aquatic organisms excrete ammonia through skin ex. Starfish. Mammals loose small amount of water in the form of sweat or oils. Ex- human.
2. Sweat glands: The sweat glands pass out sweat present on skin throughout body. When body temperature rises, these glands secrete sweat.
3. Oil glands/sebaceous glands: pass out sebum through skin & contains fatty acid, waxes, steroids & oils.
4. Lungs: Co₂ & water formed in respiration lungs removes Co₂ & water vapours in expiration.
5. Liver: It has 2 pigments bilirubin (yellow) & biliverdin (green) that pass into anus through bile juice & passes out of body in faeces.
6. Large intestine: It passes calcium, iron & magnesium ion into faeces.
7. Gills: Remove Co₂ in aquatic animals.