This vehicle is known by two names, "Field Car 4 Seater 4x2" and in this version for the US Marine Corps, "Automobile, Chevrolet, Cross Country".
Based on a 1930 Chevrolet 1/2 ton commercial chassis. Some were also based on the 1929 chassis.
America's attempt at a "Kublewagen" in much the same vein as the early German versions.
This version could mount two .30 caliber Browning Machine Guns and also had a BAR rifle for close in protection. The machine guns were set up to fire to the front and the rear.
Not very effective, I suspect.
I actually have a copy of this photo that I got from the Marine Corps archives maybe 40 years ago.
Bill