One can observe mucus dripping from the nostrils of stallions after they flehmen.

There was kippered salmon, and Finnan haddocks, and a lamb's head, and a haggis[…]

July 31, 2015, Michiel van Wyk, Sabine Schneider, Sonja Kleinlogel, “Variable phenotypic expressivity in inbred retinal degeneration mouse lines: A comparative study of C3H/HeOu and FVB/N rd1 mice”, in Molecular Vision, volume 21:

In addition to book lungs most spiders also have a second respiratory system in the form of paired tracheae; Atypus has none.