Like all trilobites, the body is divided into three functional segments known as tagmata ( singular : tagma ), which in turn are divided into three lobes-the central lobe ( axial ) and two lateral lobes ( pleural ).
22.
The rank dates to captain ) and inferior to an " Antisyntagmatarchis " ( Lieutenant Colonel ), and held either usually by battalion ( " tagma " ) executive officers ( battalions are typically commanded by Lieutenant Colonels ).
23.
Judging from the unit's name and the peculiar titles of its officers, it also had a considerable ancestry, dating back to the East Roman army, but it is unknown exactly when it was constituted as a " tagma ".
24.
In trace fossil classification schemes based on behavior, the body imprint is considered a cubichnion, or resting trace . " Cheliceratichnus lockleyi " exhibits the tagma characteristic of arthropods, with the trace divided into anterior, central, and posterior regions.
25.
Consequently, in the 11th century, the distinction between " imperial " and provincial forces largely vanished, and the term " tagma " was applied to any permanent formed regiment, and regional origins and identities are prominently displayed in the units'titles.
26.
Michael received the " tagma " of the Excubitors ( one of the professional guard cavalry regiments stationed around Constantinople ), and Thomas the " tourma " ( division ) of the " Foederati ", stationed in the Anatolic Theme.
27.
At the same time, however, the presence of a " tagma " ( professional standing regiment ) called the " Stratlatai " is attested in Asia Minor in the late 10th century, formed by Emperor John I Tzimiskes ( r . 969 976 ).
28.
Only Yahya of Antioch records that in summer 971, with 12, 000 men, he oversaw the repairs carried out to the walls of Antioch following an earthquake and executed one of the murderers of tagma " of the " Stratelatai " in the army of Bardas Skleros.
29.
The " kandidatoi " are still mentioned in the 10th-century work " De Ceremoniis ", but the title had become nothing more than a palace dignity, fulfilling a purely ceremonial role and entirely separate from the " tagma " of the " scholai ".
30.
In the latter half of the 10th century, probably under Romanos II ( r . 959 963 ), the regiment, like the senior-most " tagma ", the " Scholae ", was split in two units, one for the West and one for the East, each headed by a respective Domestic.
