McGregor Museum

The Coelenterata are an obsolete taxon used to group together the Cnidaria, Ctenophora and Porifera.  The Hexactinellida are thought to be a basal group of the Porifera because of their simple, mainly asconoid, cup shape (1 – 7).  Other evidence for this hypothesis are their simple, siliceous, four or six pointed spicules (a & h), the presence of a syncitial epidermal layer (indiscrete cells characterised by a large cytoplasm and many nuclei) and their inability to retract the feeding choanocytes in response to stimuli.  Many of the other spicules pictured here (letters besides a & h) are probably broken or malformed spicules as environmental conditions play a large role in spicule formation.

The Coelenterata are an obsolete phylum which encompassed sponges and Cnidarians (with ctenophores within Cnidaria).  The  order Porifera is now classified as a phylum containing all filter feeding sponges.  The most basal of the eumatetazoan phyla, Porifera are derived from the sister taxon to eumetazoans, single celled choanoflagellates.  This wall chart shows representative body forms (1-4), internal structures (5-8) and spicule shapes (7 & 9) of an obsolete class now distributed throughout Porifera.  The group Lithistida has been retained as an order whose members are mainly known as fossils but still have some extant representatives.

The order Anthoathecatae has many synonyms due partly to the length of time and number of people who have studied the interesting phylum Cnidaria.  Shown here are some solitary, free swimming medusa (1, 7 & 8 ) which are either male or female, a hydroid stage (9) which reproduces asexually either through budding of other hydroids, medusa or both (shown here as a complex hydroid).  Development of a medusa (evidently from a holomedusoid species) shows the progression of both endo- and ectoderm (en & ek respectively) (4, 5 & 6).

Sketches of hydra showing the stinging cnidocytes both armed and released (top left), asexual reproduction via budding (left and middle extended adults), sexual reproduction with ovum (Ov) and spermatazoa (Spz) (right two extended adults).

The Coelenterata are an obsolete phylum which encompassed sponges and Cnidarians (with ctenophores within Cnidaria).  The Ctenophora (comb jellies) are divided into two classes depending on presence of tentacles with the vast majority of species in Tentaculata.  This Wall Chart illustrates the body forms of some Ctenophores, note only two tentacles (when present), the rows and/or clumps of cilia which beat to produce movement (produce rainbow effect in doing so), and the presence of a through gut.  Interesting to note is the elongate body plan (fig. 4) of a repersentative of the family Cestidae which moves via undulations throughout it’s length.

The Coelenterata are an obsolete phylum which encompassed sponges and Cnidarians (with ctenophores within Cnidaria).  The  phylum Porifera is now classified as the most basal of the eumatetazoan phyla being derived from the sister taxon to eumetazoans, single celled choanoflagellates.  This wall chart shows representative body forms and spicule shapes of an obsolete order now mainly classified under the Subclass Tetractinomorpha.

The Coelenterata are an obsolete phylum which encompassed sponges and Cnidarians (and Ctenophora within Cnidaria).  The  phylum Porifera is now classified as the most basal of the eumatetazoan phyla being derived from the sister taxon to eumetazoans, single celled choanoflagellates.  This wall chart shows some organisation of sponge filtration systems (1, 2, 4, 5 & 9) as well as the structure of some spicules (7, 8, 11 & 13) that are the mineralised fraction of the sponge body and are bound together by the protein spongin.