General Zoology Handout
Lab 3
Phylum: Porifera: Exercise 7
Animals in this phylum are all metazoans (multicellular). They have little or no tissue
organization and are said to be at the cellular level of organization. Important terms:
pores, canal systems, spongocoel, radial canal, incurrent canal, choanocytes, spicules
and osculum. Sponges have canal systems running throughout their bodies that are one
of three types: asconoid, syconoid or leuconoid (Figure 7-1 on page 110). Understand
these three types of body plans. Look at slides of Grantia choanocyte (refer to Figure 7-1
pg 110), pay special attention to the Radial Canal, Spongocoel, Apoplyle,
Choanocytes. Sketch what you see. Look at the domo slides of Spongilla Spicules and
Gemmules (Fig 7-6 pg 114 and 7-2 pg 111). Look at the preserved specimens scattered
around the room and try to classify them down to class. You are responsible for the
information on pages 109-115.
Class Calcarea: all marine; spicules of calcium carbonate (same compound as
mammalian bone matrix); canal systems are asconoid, syconoid or leuconoid.
Class Hexactinellida: all marine; siliceous 6-rayed spicules often unite to form a
network; body often cylindrical or funnel shaped; canal system syconoid or
leuconoid.
Class Demospongiae: some freshwater, most marine; commercial bath sponges are in
this class, canal systems are leuconoid
Phylum: Cnidaria: Exercise 8
Cnidaria are radiate animals. They have radial symmetry (around one central axis like a
circle) and are in what is called the tissue level of organization because they have tissues
but no true organs. Radiate animals all have the following list of features: 2 primary
germ layers, a gastrovascular cavity (GVC) opening to the outside by a mouth enabling
some radiates to have a hydrostatic skeleton. Cnidarians have two main types of body
forms, polyp and medusa, somewhere in their life cycle. Look at the preserved
specimens and the slides of the Cnidaria that are available in the lab. You are responsible
for the specimens and information on pages 119-132.
Class Hydrozoa: both polyp and medusa represented, found in fresh water and
marine. Look at the slides of the Hydra and Obelia. Additionally look at the
preserved specimens. Sketch the Hydra (Fig. 8-1) and the Obelia. Sketch a
cnidocyte (Fig. 8-1). Note and try to identify the following: tentacles, hypostome,
mouth, cnidocyte, nematocyst, gastrovascular cavity.
Class Scyphozoa: solitary, polyp reduced, true jellyfish; Look at the specimens in the
back of the room, and try to identify the following: tetramerous radial symmetry,
umbrella, mouth, ring canal, oral arm, tentacle.
Class Anthozoa: all polyp, GVC subdivided by mesenteries, corals and anemones;
Look at the specimens in the back of the room, and try to identify the following:
pedal disc, oral disc, mouth, tentacle.