Exctretion
Hermit crabs excrete mainly through their antennal glands on the anterior end of their body. Supplying the wastes to these glands is an anterior vesicular mass is located in the chephalothorax. A posterior vesicular mass is located in the pleon, and essentially serves the same function as the anterior one, only it connects to the posterior bladder instead, (Tudge, Asakura & Ahyong, 2004.) Hermit crabs are also ammonotelic, which means they are able to excrete soluble ammonia, and they do this across their gill epithelia. Decapods have nephridia, which control ion concentration, eliminating ions like Mg2+ and and SO42- but retaining Ca2+ and K+. Marine crabs lack any sort of excretory canal unlike crayfish, and rid their wastes by osmoregulation, (Ruppert, Fox & Barnes, 2004; Tudge, Asakura & Ahyong, 2004.) |