Three-dimensional structure of the nasal passageway of a hagfish and its implications for olfaction.

From high-resolution (65 μm) data acquired by magnetic resonance imaging, we have reconstructed the nasal passageway of a single adult hagfish specimen (probably Eptatretus stoutii). We have used this reconstruction to investigate how the anatomy and morphometry of the nasal passageway influence the olfactory ability of the hagfish. We found that the long, broad section of the passageway preceding the nasal chamber will delay the response to an odor by 1-2 s.

Functional morphology of the nasal region of a hammerhead shark.

We describe several novel morphological features in the nasal region of the hammerhead shark Sphyrna tudes. Unlike the open, rounded incurrent nostril of non-hammerhead shark species, the incurrent nostril of S. tudes is a thin keyhole-like aperture.