Variations in the morphology of saccular otoliths (sagittae) among three sympatric species of the genus Serranus (S. atricauda, S. cabrilla and S. scriba) from the Canary Islands were investigated. Although the otolith gross morphology was similar among species, S. scriba was distinct in having a rostrum which had a slight turning at the tip and a more funnel-like ostium. The shallower water species (S. scriba) had otolith and sulcus areas which were smaller than the deeper water species (S. cabrilla and S. atricauda). The sulcus acusticus and ostium size were correlated with the habit depth of the species, with the highest values in the deepest species, S. cabrilla. The otolith outline shape indices changed with size (total length) of the species, and allowed the separation of the species by means of a discriminate function.

The connections of the olfactory bulbs of Podarcis hispanica were studied by tract-tracing of injected horseradish peroxidase. Restricted injections into the main olfactory bulb (MOB) resulted in bilateral terminallike labeling in the medial part of the anterior olfactory nucleus (AON) and in the rostral septum, lateral cortex, nucleus of the lateral olfactory tract, and ventrolateral amygdaloid nucleus. Bilateral retrograde labeling was found in the rostral lateral cortex and in the medial and dorsolateral AON. Ipsilaterally the dorsal cortex, nucleus of the diagonal band, lateral preoptic area, and dorsolateral amygdala showed labeled cell bodies. Retrogradely labeled cells were also found in the midbrain raphe nucleus. Results from injections into the rostral lateral cortex and lateral olfactory tract indicate that the mitral cells are the origin of the centripetal projections of the MOB. Injections in the accessory olfactory bulb (AOB) produced ipsilateral terminallike labeling of the ventral AON, bed nucleus of the accessory olfactory tract, central and ventromedial amygdaloid nuclei, medial part of the bed nucleus of the stria terminalis, and nucleus sphericus. Retrograde labeling of neurons was observed ipsilaterally in the bed nucleus of the accessory olfactory tract and stria terminalis, in the central amygdaloid nucleus, dorsal cortex, and nucleus of the diagonal band. Bilateral labeling of somata was found in the ventral AON, the nucleus sphericus (hilus), and in the mesencephalic raphe nucleus and locus coeruleus. Injections into the dorsal amygdala showed that the mitral neurons are the cells of origin of the AOB centripetal projections. Reciprocal connections are present between AOB and MOB. To our knowledge, this is the first study to address the afferent connections of the olfactory bulbs in a reptile. On the basis of the available data, a discussion is provided of the similarities and differences between the reptilian and mammalian olfactory systems, as well as of the possible functional role of the main olfactory connections in reptiles.

The amygdaloid formation of the lizard Podarcis hispanica can be divided into three main groups of nuclei on the basis of their input from the main and accessory olfactory bulbs: the vomeronasal amygdala, the olfactory amygdala and the dorsal amygdaloid group, the latter group receiving afferents from neither the main (MOB) or the accessory olfactory bulb (AOB). The vomeronasal amygdala has a centrifugal projection to the AOB, an important commissural connection to the contralateral vomeronasal amygdala, a minor projection to nucleus accumbens, and a bilateral projection to the lateral cortex. The olfactory amygdala displays a bilateral afferents from the MOB, receives a contralateral afferent, and is reciprocally connected with the lateral cortex. Moreover, it receives an important input from the vomeronasal amygdala. The dorsal amygdaloid group receives projections from the other two amygdaloid groups, multimodal inputs from the anterior dorsal ventricular ridge and the dorsal cortex, and a putative cholinergic input from the basal telencephalon. Moreover, it is the site of origin of a prominent bilateral amygdalo-striatal projection that extends to the bed nucleus of the stria terminalis and the so-called amygdalo-striatal transition area, through which it may control both visceral and motor activities. The main extratelencephalic output of the amygdala courses through the stria terminalis and terminates in the ventromedial hypothalamic nucleus. The extratelencephalic afferents of the amygdala arise from several hypothalamic and anterior thalamic nuclei, from the mesencephalic and rhombencephalic aminergic cell groups, and from the rhombencephalic parabrachial nucleus.

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