Some fossil sponges are classified by the mineral composition of their spicules. Chaetetids are rather odd fossils which you will see in the lab this week. Give me two reasons why they are now classified with the sponges. Now ALL of you can tell me what booboo the author made in this statement. Be sure to use the web often on this topic.
Brachiopods have a characteristic lophophore .
Brachiopods were among the most common marine animals in the Paleozoic, but now there are only about 120 genera alive, and most of them rare. Please give an example. Now for the Phylum Mollusca, in all its glory. On Thursday we will discuss evolutionary models for the Phylum Mollusca. Of importance will be the subphyla of Amphineura, Diasoma and Cyrtosoma.