Missing O-Rings ??

[LenS]

Just started the build on RS Max Nano and I'm either not understanding something, or parts may be missing.  

 

The pump for the protein skimmer doesn't seem to have any o-rings and it really doesn't seat at all into the skimmer body.  I can put the outlet from the pump into the bottom of the skimmer body, but if you lift up on the body, the pump falls right out.

 

Am I missing an o-ring (I haven't seen any in the packaging - or on the pump itself) OR, am I not understanding how the pump mates up the skimmer body????

 

Thanks,

 

Len