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Conventional carbohydrate histochemistry and the binding patterns of 21 lectins were analysed to characterise the glycoconjugate content in the components of the vomeronasal organ of the armadillo Chaetophractus villosus. The mucomicrovillous complex of the sensory epithelium bound most of the lectins studied. No reaction was observed with Con A, PSA, S-Con A and SBA, and the sustentacular cells were-stained with UEA-I, DSL, LEL, STL and Con A. The vomeronasal receptor neurons were labelled with S-WGA, WGA, PNA, UEA-I, STL, Con A, S-Con A, ECL and RCA120. The basal cell layer reacted with S-WGA, WGA, LCA, UEA-I, DSL, LEL, STL, Con A, JAC and VVA. The nonsensory epithelium exhibited a differential staining in relation to the different components. The mucociliary complex stained with ECL, DBA, JAC, RCA120, STL, LCA, PHA-E, PHA-L, LEL, BSL-I and VVA. However, SJA and UEA-I stained the mucus complex lining a subpopulation of columnar cells. The cytoplasm and cell membranes of columnar cells was labelled with DBA, DSL and LCA. The apical region of these cells exhibited moderate reactivity with LEL and SJA. None of the lectins bound specifically to secretory granules of the nonsecretory cells. Basal cells of the nonsensory epithelium were labelled with DSL, LEL, LCA, BSL-I and STL. The vomeronasal glands showed a positive reaction with WGA, DSL, LEL, LCA, DBA, PNA, RCA120 and SBA. Subpopulations of acinar cells were observed with ECL, S-WGA, Con A, S-Con A and DBA. PNA and RCA120 stained the cells lining the glandular ducts. In comparison with previous results obtained in the olfactory mucosa of the same group of armadillos, the carbohydrate composition of the vomeronasal organ sensory epithelium differed from the olfactory sensory epithelium. This is probably related to the different nature of molecules involved in the perireceptor processes.

The ultrastructure of the olfactory mucosa of the armadillo Dasypus hybridus was studied. A comparison with the olfactory mucosa of another armadillo (Chaetophractus villosus) was made. The olfactory mucosa of D. hybridus shows many features which are similar to those of other mammals. Interestingly, it differs from the olfactory mucosa of the armadillo C. villosus. A suggestion is made that these differences may be due to differences in the digging habits of these species. In Dasypus, the supporting cells (SCs) showed dense vacuoles, multivesicular bodies and lysosome-like bodies probably related with the endocytotic system. The SCs show a dense network of SER presumably associated with xenobiotic mechanisms. The olfactory receptor neurons exhibit lysosome-like bodies and multivesicular bodies in their perikarya. These organelles suggest the presence of an endocytotic system. Duct cells of Bowman's glands exhibit secretory activities. Bowman's glands are compound-branched tubulo-acinar mixed glands with merocrine secretory mechanisms.

Conventional histochemistry and the binding patterns of 22 biotinylated lectins were examined for characterisation of glycoconjugates in the components of the olfactory mucosa of the armadillo Chaetophractus villosus. The mucous lining the olfactory epithelium showed binding sites for DSL, WGA, STL, LEL, PHA-E and JAC. Only the basilar processes of the supporting cells stained for Con-A and S-Con A. The olfactory receptor neurons stained with LEL, LCA, Con A, S-Con A, JAC and PNA. The layer of basal cells did not react with any of the lectins studied. Bowman's glands in the lamina propria showed subpopulations of acinar cells reacting with SBA, S-WGA, WGA, STL, Con A, PSA, PNA, SJA, VVA, JAC and S-Con A, but in our optical studies with lectins we were unable to differentiate between mucous and serous cells in the way that is possible on electron microscopy. The ducts of Bowman's glands were labelled with S-WGA, STL, LEL, PHA-E, BSL-I and JAC. This histochemical study on the glycoconjugates of the olfactory mucosa in the order Xenarthra provides a basis for further experimental investigations.

The sense of olfaction in armadillos plays an important role, suggested by the great development of the nasal structures, olfactory bulbs, and related brain regions. The mammalian olfactory mucosa is a privileged site of neuronal death and regeneration during the whole life span. A detailed knowledge of its ultrastructure is convenient for gaining insight into the factors controlling those phenomena. We performed this work in species not previously studied in order to provide a firm basis for further research on those factors. No information is available on the histology and ultrastructure of the olfactory mucosa in the order Xenarthra to which armadillos belong. Samples from the endoturbinals of the armadillo Chaetophractus villosus were prepared for light and electron microscopic examination by the usual conventional means. The olfactory epithelium of Chaetophractus villosus shows the classical three types of cells: supporting cells, olfactory receptor neurons, and basal cells. The olfactory neurons and the basal cells were similar to that described in other species. Two different types of supporting cells are described. An outstanding characteristic of the supporting cells is the normal presence of abundant phagosomes, apical secretory granules, apocrine-like protrusions, and highly developed smooth endoplasmic reticulum. Apoptotic bodies are frequently found in the infranuclear cytoplasm of supporting cells. The ductular epithelium of Bowman's glands reveals secretory activity. The lamina propria shows mixed Bowman's glands. Great development of smooth endoplasmic reticulum is observed in the mucous acinar cells. Evidence for merocrine and apocrine mechanisms in the Bowman's glands is presented. The presence of apoptotic bodies and phagosomes in supporting cells suggests a participation in the cellular events induced by cell death and proliferation of the olfactory epithelium. The variety of characteristics exhibited by the supporting cells of the olfactory mucosa may contribute to a deeper understanding of their scarcely known functions.

The most salient neuroanatomical features of the brain of the seven banded armadillo Dasypus hybridus are described. The microscopic characteristics were studied by serial transverse and sagittal paraffin sections, stained with Nissl and Klüver-Barrera technique. This analysis comprises the telencephalon, diencephalon and mesencephalon. The most outstanding features of this brain are: 1) Great development of rhinencephalic structures (olfactory bulbs, olfactory tubercles, anterior commissure and pyriform cortex). 2) The relative size of the induseum griseum strongly suggests that this animal would be useful for a variety of studies on this structure. 3) The high position of the rhinal fissure on the lateral hemispheric wall determines the smallness of neocortex. Therefore, this armadillo is also useful for decortication studies. 4) Absence of a distinct pineal organ. 5) Conspicuous subfornical and subcommissural organs. 6) Absence of a distinct intermediate lobe in the hypophysis.