Unformatted text preview: absent (octopods). In these animals part of the head is modified into tentacles for capture of prey and manipulation of objects, and the foot forms a siphon for jet-propelled locomotion. ECDYSOZOA: These animals, like the Lophotrochozoa (seen in earlier in the semester), are grouped on the basis of molecular evidence. However, both phyla in this group display ecdysis , or molting of the outermost layer. Phylum Nematoda (round worms) Nematodes are pseudocoelomate, unsegmented, round in cross section, tapered at both ends, covered by a resistant, secreted cuticle , and lacking in appendages. Nematodes are widespread and common; they can be either free-living or parasitic. On display are Enterobius (pinworm) and Ascaris . In both species, the male is smaller and has a hooked posterior end....
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- Fall '11
- Biology, Enterobius, sea slugs, hooked posterior end, single spiral shell, cuttlefishes