10th Space Marine in Aliens

Maybe some one out there can tell me who the '10th Space Marine' is in
Aliens. When the Marines first enter the complex they move up in two 5 man
squads. Its been a while since I watched it but I'm pretty sure there are
distinct shots of the two squads moving into position each with 5 men in
them.

You can match all the Space Marines as being somewhere either in the drop
ship, APV, or attempting to get into the complex, but if you went through
all the names from the computer readout as they wake from hibernation or
based on most of them getting named as they die, there should only be 9
Space Marines attempting to enter the complex instead of 10.

Gorman is in the APV
Spunkmeyer and the woman pilot are in the drop ship (I forget her name).
Each of the squads has a leader, Apone and Hicks.
Each of the squads has a heavy weapon, Vasquez and Drake.
That leaves 3 marines to make up the remainder in each squad, but only 4 get
killed later in the complex and Hudson survives for a while later.
Hudson, Frost, Crowe, Deitrich and Wierzbaski (apologies on the spelling but
you know the guy I mean I hope). That just leaves the 10th unnamed marine.

Anyone shed any light on this?

Thanks in advance.