observed in the Gran Chaco. 217 



noticeable species about the laguna were the Chaja [Chauna 

 cristata) , Ducks [Dendrocycna fulva) in flocks, Ibises [The- 

 rlsticus melanopis) also in occasional flocks, Lapwings 

 {Belonopterus cayennensis), and Herons, of which Ardea 

 cocoi was the most common. Syriyma sibilatriv was ob- 

 served at times, and I must not forget to mention the Toco 

 Toucan {Rhaniphastos toco), of which small companies were 

 often noticed flying across from one piece of woodland to 

 another. 



On the western side of the river the country was typical 

 Chaco savannah, while upon the very margin, just opposite 

 Concepcion, was a narrow strip of fine *' monte " or wood, 

 in which the most striking birds were the Blue Jays {Cyano- 

 corax chrysops and C. ccerideus). Hanging from the trees 

 were many nests of Amblycercus soliturius and Cassicus 

 albirostris, those of the former being larger and formed 

 of brown fibres, those of the latter smaller and of finer 

 black fibres. In passing I may mention one or two of the 

 characteristic mammalian inhabitants : Agoutis were fre- 

 quently seen, and two species of Opossum were fairly 

 plentiful (Didelpkys azarce and D. crassicaudatd). By the 

 river-margins the Carpincho [Hydrochcerus capybara) was 

 common, and occasionally we saw an Otter (probably either 

 Lutra brasi/iensis or L. paranensis). The water close to 

 the Chaco shore was shallow, and here the Indians speared 

 the dreaded Sting-ray [Taniara duinerili). On the low- 

 lying island in the middle of the river, birds were plentiful, 

 amongst which Ground- Warblers [Geothlypis velata), Sal- 

 tators, Finches {Speyinophila palustris, Paroaria capitata), 

 Oven-birds (Furnarius rufus), and Bush-Shrikes {Thamno- 

 philus radiatus) were perhaps the most common. 



On the evening of October 20th we embarked upon a small 

 steamer, with our horses and stores in a lighter lashed along- 

 side, and started up stream for Caraya Vuelta. In the trees 

 overhanging the river were many Cormorants, and in similar 

 positions the Darter [Plotus anhinga) was abundant, sitting 

 for the most part on some dead tree with its wings half 

 expanded. We also saw a few Muscovy Ducks [Cairina 

 moschata), an occasional Trogon [Trogon surucurd), and, 



