Sj. Rehorek et al., The structure of the nasal chemosensory system in squamate reptiles. 2. Lubricatory capacity of the vomeronasal organ, J BIOSCI, 25(2), 2000, pp. 181-190
The vomeronasal organ is a poorly understood accessory olfactory organ, pre
sent in many tetrapods. In mammals, amphibians and lepidosaurian reptiles,
it is an encapsulated structure with a central, fluid-filled lumen. The mor
phology of the lubricatory system of the vomeronasal organ (the source of t
his fluid) varies among classes, being either intrinsic (mammalian and caec
ilian amphibian vomeronasal! glands) or extrinsic (anuran and urodele nasal
glands). In the few squamate reptiles thus far examined, there are no subm
ucosal vomeronasal glands. In this study, we examined the vomeronasal organ
s of several species of Australian squamates using histological, histochemi
cal and ultrastructural techniques, with the goal of determining the morpho
logy of the lubricatory system in the vomeronasal organ. Histochemically, t
he fluid within the vomeronasal organ of all squamates is mucoserous, thoug
h it is uncertain whether mucous and serous constituents constitute separat
e components. The vomeronasal organ produces few secretory granules intrins
ically, implying an extrinsic source for the luminal fluid. Of three possib
le candidates, the Harderian gland is the most likely extrinsic source of t
his secretion.