CRAYFISHMAN!!

The digestive system consists of the foregut, which includes an enlarged stomach, part of which is specialized for grinding; the midgut, which extends from the foregut; and the hindgut, which leads to the anus and functions in water and salt regulation. The digestive gland secretes digestive enzymes and aids in the absorption of the products of digestion.

The circulatory system is centered around a muscular heart with dorsal, anterior, and posterior arteries leading away from it. Branches of these vessels empty into the sinuses of the hemocoel. The ventral sinus collects the blood, the blood travels through the gills, and then returns to the pericardial sinus surrounding their heart.

The nervous system is composed of a ventral nerve cord fused with segmental ganglia, and the supra esophageal and sub esophageal ganglia. Giant neurons in the ventral nerve cord function in escape responses. The supra esophageal and sub esophageal ganglia control the head appendages in response to sensory input received from receptors.

The excretory system are also called the antenna glands because they are located at the base of the second antenna. They excrete the waste products of blood filtration; ammonia is the primary waste product. Ammonia is also excreted across the gill surfaces and by diffusion across thin parts of the exoskeleton .

Arthropods like these crayfishes are mostly found in rocky tributary streams and rivers, and rocky areas along the shoreline.