Fringe Connections

Walter used the same neural halo in "The Box" as he used on the child in "Inner Child".

Marshall Bowman had a disk in his hand like John Scott and the woman in 'The Ghost Network'.

A seahorse can be seen on the Bishops' refrigerator.

Olivia has excellent aim in "Bound"; she killed Loeb's wife with a single shot to the head. It's stated in "Olivia" that Fauxlivia won an Olympic gold medal for marksmanship.

Olivia pulled up a list of the frozen heads found in S02E04 'Momentum Deferred' and they were all marked with "2E204", a reference to the episode in which they were stolen.

A frog can be seen outside the entrance to the daycare center.

In "The End of All Things" September said that he made a mistake when he distracted Walternate in his lab in "Peter" and saving Walter and Peter from the icy lake was an attempt to rectify that mistake.

The opening crawl is an homage to Blade Runner.

The hand glyph can be seen on a door in the pocket universe.

There was a white tulip in Walternate's bedroom in "Immortality" when he was struggling with what he had to do to save his world, suggesting that the symbol has meaning for him just like it did for Walter in "White Tulip".

William Bell left Massive Dynamic to Walter.

A seahorse can be seen hanging from the taxi when Walter listens to music.

The radioactive isotope compound from "The Cure" that caused heads to explode was used as a weapon against the Observers in "An Enemy of Fate".

The episode ends with September going into December's apartment, apartment 513, the episode code of the next and final episode of the series.

The apple glyph can be seen on a door in the pocket universe.

In "The End of All Things" September told Peter about Henry, the son he never knew existed, who was born in "Bloodline".

Jones said there are 10 tests for Olivia in total. The first was a box of lights that Olivia had to turn off with her mind.

The frog glyph can be seen on a door in the pocket universe.

The rollercoaster seen from atop the World Trade Center in Olivia's mind in "Lysergic Acid Diethylamide" is a reference to the one she rode with Ella in "August".

All of the people in Olivia's mind wear blacks and greys because Cortexiphan subjects have a strong desire to blend in.

A hand can be seen on the wall when Olivia and Peter attack the Observers and Loyalists.

The Observers read Nina's phone call from the impressions her sound waves made on the glass in her office in "Anomaly XB-6783746", like Peter did in to hear the phone call Nancy Lewis made in "The Road Not Taken".

Jones is working with Bell, who is alive.

A seahorse can be seen in Walter's Monty Python trip.