Molecular clouds in M31 and M33

CO emission has been detected toward a number of H II regions in M31 and M33. Most of the emission in the direction of the Baade and Arp H II regions in M31 appears to originate in small molecular clouds. The emission from giant molecular clouds (GMCs) accounts for only about one quarter of the CO emission. Specific predictions are made about what would be observed at very high resolution. There is no evidence that the GMCs in M31 are different from those in the Galaxy. The peak line strength and line width show no significant radial dependence in M31, but the integrated line strength does show significant decrease with galactic radius. No individual GMC in either M31 or M33 is observed with an integrated line strength over 3.2 K km/s, indicating that the clouds have a natural size limit which may be tidally determined.