Order AULOPORIDA, ?Lower Ordovician - Upper Permian. Tube-like corallites grow up next to each other communicating by pore tunnels (Syringoporicae, Fig. 5A) or are reptant and encrusting surfaces with mural pores (Auloporicae, Joon. 5B). Septal spines are present and tabulae may be absent. Syringoporids are abundant in upper-Silurian outcrops in Saaremaa (Lõo and Katri cliffs). Syringopora affabilis has a peculiar symbiosis with stromatoporoid. Syringopora multifaria is more common. Encrusting Aulopora amica is abundant in Katri cliff.