Anatomy of finfish and shellfish

Unit 12 - Arthropoda

12.2.5. Excretory System
The kidneys of lobsters, like those of shrimps, are known as antennal glands. More compact than in shrimps, the kidneys of lobsters have a pale olive-green hue and thus are often called green glands. They lie on each side of the body, below and in front of the foregut. Urine that is formed in a glandular portion passes into tubes that enter a duct leading from a dorsally situated bladder. There is no direct connection be¬tween bladder and glandular portion, so the bladder can be filled only when urine backs up through this duct. Subse¬quently, the urine is released to the exterior via the same duct, which opens on the basal segment of the antenna.