A) Three-dimensional reconstruction of the right nasal fossa in adult agouti (Dasyprocta leporina), with a dashed line indicating a cross-sectional level within the olfactory recess at the level of the first and second ethmoturbinals (etI and etII, respectively). A histological section at a similar level from a second specimen (Dasyprocta cristata) is shown in B). Here, a thick olfactory mucosa is found along adjacent surfaces of the semicircular lamina (scl) and septum (s), as well as the dorsal part of ET I. Note that little olfactory mucosa extends rostral to this point (see A, where the estimated distribution of olfactory epithelium is indicated in green). Bottom row: enlarged views of mucosa of the scl (C), etI (D), and septum (E). Note thick olfactory epithelium (oe) overlaying a deep lamina propria that includes numerous olfactory nerve bundles (on). Scale bars: a, 3 mm; b, 1 mm; c–e, 30 µm.