Tetilla (sponge)
Tetilla is a genus of demosponges in the family Tetillidae. It is widely distributed. They are mainly found in deeper habitats.
Description
These globular sponges lack porocalices and auxiliary megascleres. The surface is covered with conical elevations or uniformly covered in minute spines. They have few oscules. These are typically located at the top. Spicule strands at the base act as a root system, attaching the sponge to the substrate. There is no visible cortex when a cross-section is taken.The spirally radiate skeleton is made of bundles of oxeas originating from the center of the sponge. These become mixed with triaenes, mainly protriaenes. The microscleres are sigmaspires. These are absent in the type species.