The recent collection of 13 specimens of the Tanzanian endemic Adenorhinos barbouri more than doubles the number of known specimens of this rare viper. Internal and external characters were examined in the older and the more recently collected specimens and character variation has been summarized. Based on limited information from collectors' notes and dissection of the alimentary canal, A. barbouri appears to be a species of the forest floor; both juveniles and adults prey on earth-worms and adults may also feed on anurans.