Starfleet Marine Corps
Organisation
Marines are Organised into Squads, Platoons and Regiments. On Starfleet ships (Not including the Khan Class) marines are only organised into Squads and platoons due to the amount of marines present not being able to make up a platoon.
Squads: Squads are made up of 10 marines. A standard marine formation will include a single officer per squad although this may vary on ships depending on the amount of officers present. A squad is made up of the following:
1 Officer
1 Sapper (explosives/demolitions expert)
1 Communications Specialist
1 Combat Medic
1 Combat Engineer
1 Heavy Weapons Operator
1 Recon Specialist
1 Computer Systems Specialist
2 Riflemen
Although all of the marines in a squad specialise in something they all are still heavily trained in shooting the enemy and other basic skills (I.e Tracking). The Heavy weapons Operator would carry a Heavy Weapon (Isomagnetic Disintergrator/Photon Mortar/Photon Cannon).
Platoon: Platoons are made up of 5 squads of Marines (50 men). The officer commanding the First Squad would be Platoon Commander.
Regiment: Regiments are made up of 5 Platoon's (250 men). Regiments also contain heavier Armour:
8 M'ran Tanks
2 Karok Long-Range Artillery (LRA)
3 Warthog APC's each capable of carrying a squad of marines.
Marine's rarely fight in formations of Regiments. The Khan class assault ship is capable of carrying 3 full Regiments but is very rarely crewed with this amount. Regiments are usually stationed on key planets (Earth, Vulcan, Trill, Andoria etc.).