It might have failed updating for some reason and uninstalled. Try finding it in the market.
One weird thing I see is that Google+ shows up as one of my not installed apps in the "my apps" list. It comes pre-installed and seems to work, so I'm not sure what that other one is and how it differs.
Sent from my Galaxy Nexus using Tapatalk
Nexus 4 16GB + Rearth Ringke Slim
N4 Bumper: In storage
GSM Galaxy Nexus 16GB: In storage
GSM Nexus S: Gave to Wife
T-Mobile G2: In storage
Nexus One (T-Mo Bands): In storage
T-Mobile G1: In storage
HTC Tilt 2: Trashed
Nokia E61i: In Storage