It is Marmon-Herrington CTL-3M light tank. Initially built as the CTL-3 with rubber band track, they were rebuilt in 1941 as CTL-3M for the USMC and delivered in 1942. They were fitted with a vertical volute suspension system and track identical to the M2A4 Light Tank.
For more information see my website:
http://www.geocities.ws/marmonherrington/
Also of interest on my site is
The 'Marine Tank' of 1936: The Strange Case of the Marmon-Herrington Tank in the US Marine Corps by Kenneth W. Estes
HTH,
Hanno
