Fig.1. Gular sac of Rhinoderma darwini, adult male.

Proceedings of the Zoological Society of London 1888 p231
Date 1888
Source http://ia600503.us.archive.org/6/items/proceedingsofgen88proc/proceedingsofgen88proc.pdf
Author George Bond Howes (1853-1905)
Source: https://commons.wikimedia.org/wiki/File:Rhinoderma_darwinii00.jpg

Darwin's frog or southern Darwin's frog (Rhinoderma darwinii) is a rhinodermatid frog native to the forest streams of Chile and Argentina. The most striking feature of this frog is the tadpoles' development inside the vocal sac of the male.