The horn corals have long gone by the wayside, but in their hay day they must have added a certain beauty to the diorama of the Paleozoic seafloor. Some varieties dominated the scene reaching meters in length. At night they flung out their long tentacles in order to sweep up unsuspecting organisms passing by. They attached themselves to the sea floor with the narrowed ends of their exoskeletons, whereas their wide-opened top ends encased the tentacles; hence the reference to the shape of a horn.
* Horn corals were extremely abundant during the Paleozoic time slot and most were individual varieties with a few colony variety exceptions.
TWO SPECIES CLASSIFICATIONS
Scientific Name: Grewingkia, canadensis Heliophyllum
Common Name: Horn Coral Same
Kingdom: Animalia Same
Phylum: Cnardia (means to sting) Same
Class: Anthozoa (means flower animal) Same
Order: Rugosa (means wrinkled wall) Same
Suborder: Stauriida Same
Family: Streptelasmatidae Zaphrentidea
Genus: Grewingkia Heliophyllum
Species: canadensis Unknown
As a very general rule, rugose coral have stronger radial septa (septum) or vertical growth walls that radiate out from the center (like bicycle spokes). Rugose corals differ from other corals by this pattern by which they add septa through their growth. Named for their wrinkly outer skin they possessed less developed horizontal partitions, but stronger vertical ones.