Definition of courier: An individual responsible for the exchange of items between two or more parties. Couriers are usually employed by a company that charges a flat rate to the party using the courier service. Federal Express, UPS, DHL, and the United States Post Office all employ couriers to deliver mail and packages.
At least 3 bacterial morphotypes, as well as fungal mycelia, thelastomatid nematodes, and ingested material are found in the hindgut. At annual molt, the lumen bacteria virtually disappear; presumably they are replaced from anterior gut regions, ingested exuvium, and ingested soil.
The three basic bacterial shapes are coccus (spherical), bacillus (rod-shaped), and spiral (twisted), however pleomorphic bacteria can assume several shapes. Shape of Bacterial Cell Cocci (or coccus for a single cell) are round cells, sometimes slightly flattened when they are adjacent to one another. Bacilli (or bacillus for a single cell) are rod-shaped bacteria. Spirilla (or spirillum for a single cell) are curved bacteria which can range from a gently curved shape to a corkscrew-like spiral.