Tectin is an organic substance secreted by certain ciliate protozoa

Protozoa

Protozoa are a diverse group of single-cells eukaryotic organisms, many of which are motile. Throughout history, protozoa have been defined as single-cell protists with animal-like behavior, e.g., movement...

ns. Tectin may form an adhesive stalk, disc or other sticky secretion. Tectin may also form a gelatinous envelope or membrane enclosing some ciliates as a protective capsule or lorica

Lorica (biology)

In biology, a lorica is a shell-like protective outer covering, often reinforced with sand grains and other particles that some protozoans and loricifera metazoans secrete. Usually it is tubular or conical in shape, with a loose case that is closed at one end. An example is the protozoan genus...

. Tectin is also called pseudochitin

Chitin

Chitin n is a long-chain polymer of a N-acetylglucosamine, a derivative of glucose, and is found in many places throughout the natural world...

. Granules or rods (called protrichocysts) in the pellicle

Pellicle (biology)

The pellicle is a thin layer supporting the cell membrane in various protozoa, protecting them and allowing them to retain their shape, especially during locomotion, allowing the organism to be more hydrodynamic. They vary from flexible and elastic to rigid. Although stiff, the pellicle is...

of some ciliates are also thought to be involved in tectin secretion.