What is crayfish excretion?

Answer 1

The primary excretory product of crayfish is that of a small amount of ink. Due to evolution present day crayfish no longer possess a large ink bladder. This is due to the shallow water they reside in and the extra weight the bladder would have put on the animal.

Answer 2

The crayfish can excrete wastes through blood. Blood is forced through the arteries that empty into spaces within the body cavity. Once the blood has drained through these spaces and bathed the organs, it collectst in the large ventral sternal sinus. As the blood circulates, the green gland filters out waste materials. The fluid waste is then excreted through a pore just anterior to the mouth.

Answer 3

Waste is eliminated by excretory organs called "green glands."

Answer 4

The antennal gland. (or "green gland", common to crabs and other Malacostraca )