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A new body plan. The pseudocoelomates. The pseudocoelomates. Tube with in a tube plan Gut has separate entrance and exit Body space is lined by mesoderm, but only on the outer side, the endoderm lacks a mesodermal covering Constant cell number, growth of cell size rather than cell number.
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A new body plan The pseudocoelomates
The pseudocoelomates • Tube with in a tube plan • Gut has separate entrance and exit • Body space is lined by mesoderm, but only on the outer side, the endoderm lacks a mesodermal covering • Constant cell number, growth of cell size rather than cell number
The pseudocoelmate phyla • Nematoda • Caenorhabditis elegans • Rotifera • Acanthocephala
The Nematoda • Bilaterally symmetrical round worms • Lack a cellular epidermis, but instead have a cuticle. Need to molt cuticle for growth to occur • Use a hydrostatic skeleton, but in this case the fluid skeleton is separate and distinct from the gastrovascular cavity • Only have longitudinal muscles