<P> A bacillus (plural bacilli) or bacilliform bacterium is a rod - shaped bacterium or archaeon . Bacilli are found in many different taxonomic groups of bacteria . However, the name Bacillus, capitalized and italicized, refers to a specific genus of bacteria . The name Bacilli, capitalized but not italicized, can also refer to a less specific taxonomic group of bacteria that includes two orders, one of which contains the genus Bacillus . When the word is formatted with lowercase and not italicized,' bacillus', it will most likely be referring to shape and not to the genus at all . Bacilliform bacteria are also often simply called rods when the bacteriologic context is clear . </P> <P> Bacilli usually divide in the same plane and are solitary, but can combine to form diplobacilli, streptobacilli, and palisades . </P> <Ul> <Li> Diplobacilli: Two bacilli arranged side by side with each other . </Li> <Li> Streptobacilli: Bacilli arranged in chains . </Li> <Li> Coccobacillus: Oval and similar to coccus (circular shaped bacterium). </Li> </Ul> <Li> Diplobacilli: Two bacilli arranged side by side with each other . </Li>

A chain of rod-shaped cells would be called a(an)