I guess it's the P (usually phosphor) IMPlant for the source and drain regions of the PMOS.
They will get an inside P+ implant for their connections, probably the same P+ implant is used for the substrate contacts, which in this case are to be connected to the most negative voltage of the power supply (GND).
Eric, Phosphorus is n-type dopant, not p-type.
P-type is Boron and Indium.
Connecting PIMP shapes of two MOSFETs would have the same effect as connecting MOSFET's terminals in the schematic - that may be fine or forbidden, depending on the design specifics.
You are right, my statement concerning electrical connection of PIMP shapes was not correct.
It is when "PIMP AND ACTIVE" overlap, (DC) electrical connection happens.