1. foot
   1. pedal glands

1. mastax
   1. trophi

2. flame cells
3. brain
4. eyespots

1. dioecious
2. parthenogenesis (fig. 16-4)
   1. diploid amictic eggs
   2. haploid mictic eggs

• Phylum Gastrotricha (fig. 106-5)

  Gastrotricha includes small, ventrally flattened animals about 65 to 500 um long, somewhat like rotifers, but lacking the corona and mastaz. They have a characteristically bristly or scaly body.

• Phylum Kinorhyncha (fig. 16-7)

  Kinorhyncha are marine worms a little larger than rotifers and gastrotrichs, but usually not more than 1mm long.

• Phylum Loricifera (fig. 16-8)

  The Loricifera are tiny animals (0.25 mm long)that live in the space between the grains of marine gravel.

• Phylum Priapulida (fig. 16-9)

  The Priapulida are a small group (only 15 species of marine worms found chiefly in the colder waters of both hemispheres).

• Phylum Ectoprocta (fig.16-21)

  ---

• Phylum Nematoda (fig. 16-10 & 16-17; tab. 16-1)

  Known as roundworms. Nematoda live in the sea, in freshwater, and in the soil, from polar regions to the tropics.

  most numerous of all pseudocoelomates

  hydrostatic skeleton

  cuticle

  phasmids

  copulatory spicules

  Ascaris - human intestinal roundworm LC

  female adult worm in human intestines lays eggs -->
  eggs pass with feces -->
  eggs injested by human -->
  eggs hatch in to larva -->
  larva burrow through intestinal wall and enter blood stream -->
  larva go through several molts -->
  travel to lungs and exit through the aveloi -->
  these are coughed up and swallowed -->
  pass into intestines and mature into adults
  

  View this site on Ascaris lumbricoides:
  Ascaris lumbricoides
  Review LC hookworms (p. 311); trichina (p.312); pinworm (p. 312); filarial worms (p. 319)

The popular name for the Nematomorpha is "horsehair worms" based on an old superstition that the worms arise from horsehairs that happened to fall into the water, and they look something like hairs from a horse's tail.

• horsehair worms

• parasitic as juveniles

• free-living as adults

Phylum Acanthocephala (fig. 16-19 --> 16-20)

The members of the phylum Acanthocephala are commonly known as spiny-headed worms.

Phylum Entoprocta (fig. 16-21)

Entoprocta is a small phylum of about 150 species of tiny, sessile animals.

• calyx

• ciliary filter feeders

See phylogeny/Adaptive Radiation (pg. 317)

Once you have completed the lesson, you should go to Assignment 16-1.

E-mail Sylvester Allred at Syl.Allred@nau.edu

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