Afferent visual projections in three species of lungless salamanders (family Plethodontidae).

Afferent visual projections were demonstrated in three species of plethodontid salamanders by means of anterograde transport of horseradish peroxidase. On the contralateral side three optic tracts and seven neuropil areas can easily be distinguished, which are similar among the three species examined as well as in European salamandrids. On the ipsilateral side the marginal optic tract shows great diversity. The retinal projections of the latter range from weakly labeled terminal fields restricted to the thalamus to heavily labeled fields covering the entire tectum opticum.