Dear kerleone,

To answer your question correctly I should hold a copy of the Zeitschrift für Ethnologie (ZfE) in my hands. But there are only two possibilities:
1. either (Verhandlungen) is a special issue or special part of the ZfE of 1881 like a supplement with pagination in brackéts through the whole work to distinguishe it from the annual issue of the journal ZfE,
2. or the brackets refere to the (first or last) part of the ZfE containing notices, informations and varia but no full article.

Best would be to order this volume in the library and to have a look.