264 Letters from Mr. J. Graham Kerr. 



you on my return. Owing to the very unexpected length of 

 time we are staying here, I shall probably leave at once for 

 Europe on our getting out of the river, except in the very 

 remote contingency of that being before October or No- 

 vember, the season when all the plants are in flower, and 

 which, of course, I must spend up in the Chaco, in order to 

 complete, or rather " make,^' my collection of Phanerogams. 

 I find that, so far at least, the Pilcomayo shows nothing to 

 point to its name meaning " Bird-river.^' For many days 

 together, especially in the lower parts of the river, we have 

 steamed along without seeing a single bird. Now, fortu- 

 nately, things are not so bad — certain spots appearing almost 

 alive with birds — but still there are occasional days on which 

 I encounter very few. When there is practically no collect- 

 ing to be done, I try to manage a little anatomical work ; 

 and am also endeavonring to get together a collection of 

 well-preserved specimens for subsequent microscopical inves- 

 tigation. I wish especially to get a good series of specimens 

 of arthropod eyes, and also photogenic organs, in the former 

 of which I am specially interested. I had hoped that there 

 might turn up a stray species of Peripatus or some land- 

 planarians, or some other interesting archaic form, but none 

 have yet appeared. Earthworms are very rare. I have 

 searched for them at each stopping-place, but my efforts 

 were quite unsuccessful until a few days ago, when a small 

 species appeared, of which 1 have preserved a series of speci- 

 mens for Mr. Beddard. I mean, if possible, to bi'ing home 

 specimens of those two curious Woodpeckers, Leiiconerpes 

 candidns and Colaptes agricola, preserved in alcohol. I find it 

 a great drawback not knowing which of the more interesting 

 birds are least known, as regards their anatomical features, 

 and made a great mistake not inquiring into this thoroughly 

 before I started. By-the-bye, I shot two Spoonbills with 

 feathered heads and sexually immature, but with the tracheal 

 structure of Ajaja rosea. 



