We have begun a survey of the [CI] 370 μm fine structure line
and of mid-J CO line emission from ULIRGs and starburst galaxies
using our grating spectrometer ZEUS on the CSO. Here we present
observations from six ULIRGs: Mrk 231, Zw 049.057, NGC 6240, Arp 299,
Arp 220, and IRAS 17208. The CO (6-5)/FIR ratio in ULIRGs appears to
be lower for ULIRGs than for LIRGs. Comparing the CO SEDs of the
ULIRGs shows the necessity of obtaining CO rotational transitions up
to at least J = 7 to properly constrain LVG models.