What Are the Three Types of Eubacteria?

Eubacteria come in three types, each with a characteristic shape: spirilla, bacilli or cocci, according to Spark Notes. Cocci are spherical, bacilli are rod shaped and spirilla have a corkscrew form. Eubacteria are small and can be only slightly larger than most viruses. Depending on the type of eubacteria, they may or may not need oxygen to survive, according to Spark Notes.