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CAMBRIAN PERIOD

542-488 million years ago

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THE URINARY SYSTEM

Cephalochordate urinary systems utilized podocytes as do the urinary systems of vertebrates.

Amphioxus possesses podocytes (also called solenocytes, cryptopodocytes, or podosolenocytes) which are similar to vertebrate podocytes (Ruppert, from Harrison, 1997, p. 458 ). The excretory structures exist in a segmental series (Romer, p. 403) and the nephridia are intermediate between those of invertebrates and vertebrate renal tubule (Ruppert, from Harrison, 1997).

No reproductive ducts are present in lancelets or jawless fish and the both types of gametes are released into coelom (Weichert, p. 316). The females of acoels and most other flatworms lack reproductive ducts, as do lancelets and jawless fish.