Class Copepoda
</h1>

Major Attributes:
<ol>
<li>Inhabit aquatic environments, mostly marine.
<li>Adults usually <3 mm long;  some ectoparasitic forms reach
               30 cm.
<li>Free-living forms recognized by long antennae and an
               anterior medial eyespot.
<li>Filter feed on phytoplankton, but will also actively
               prey on rotifers and protists.
<li>Like all crustaceans, copepods have a cuticle, hemocoel, two
               pairs of antennae, a segmented body, paired, jointed
               appendages, separate sexes and respire through the
               body surface.
</ol>
<hr>
Description:
<p>
     The <a href = "copepoda.gif">copepods </a>can be free-living or parasitic.  The free-living
forms are usually tiny torpedo-shaped animals that swim in spurts,
using their long antennae and their thoracic appendages for locomotion.
The copepod's body is divided into a head, thorax and abdomen, but there
can be a varying number of segments in each section depending on the
species.  The parasitic forms infest the gills of fish and the gut of
mussels.  These copepods can appear worm-like or sac-like and are
often hard to recognize in the adult stage.
<P>     Copepods reproduce sexually.  The male transfers a packet of
sperm called a spermatophore to the female.  This could be in response
to a pheromone secreted by the female.  The eggs are then fertilized and the
female lays them in an external ovisac which she carries until the
nauplius larvae are released.  The nauplius undergoes several moults
to reach the copepodite stage.  After five copepodite stages, the
adult form is attained.  The entire cycle from egg to adult can take as
little as a week or as long as a year, depending on the species
involved and the availability of food.
<HR>
Some Interesting Facts:
<ul>
<li>     Copepods account for 95% of all zooplankton.  They outnumber all
other marine animals and are an important food source for other
aquatic animals.

<li> The copepod's single median eyespot is light-sensitive, therefore
giving its common name "cyclops".

<li>     The mature female often carries two pouches of brightly colored
eggs attached to the outside of her body.  Easy access to her eggs has
made her a prime target of scientists needing eggs for research.

<li> The elongated first antennae and shorter second antennae are
multipurpose.  They are used for swimming, directing a current of water
towards the filter-feeding mouthparts, and the male's anetennae are
adapted for grasping the female during mating.
</UL>
<HR>
Some Pertinent Books Found in Lamson Library:
<ol>
<LI>Banister, Dr. Keith and Dr. Andrew Campbell. 1985.<I> The
	Encyclopedia of Aquatic Life.</I> NY: Facts on File.

<li>Marshall, A.J. and W.D. Williams. 1972. <I>Textbook of Zoology:
	Invertebrates.</I> New York: American Elsevier.

<li>Thorp, James H. and Alan P. Covich. 1991. <I>Ecology and
	Classification of North American Freshwater Invertebrates.</I> New
	York: Academic Press.
</OL>
<hr>
(Betty J. Miller, Fall 1994; edited by T. Shultz, Spring 1995)