PAPERS OF GENERAL INTEREST 35 



At tlie same altitude as the Titicaca-Poopo altiplane 

 the socalled Lake Ascotan is hemmed off by a ring of 

 extinct volcanoes (only Ollagiie being active.) It is about 

 twenty-five miles in extent and lies just within the border 

 of Chile. It consists for the greater part of muddy de- 

 posits of lime salts. Numerous pools and sluggish 

 streams appear throughout, and drain away by seepage. 

 At the bases of the volcanoes along the eastward margin 

 are many waim and cold springs. These are only slight- 

 ly brackish. Small Orestias are everywhere abundant 

 here, though there is no communication with the outside. 

 Great quantities of aquatic plants of the same species 

 as those found in other lakes occur. Facilities and help 

 in fishing were kindly provided by Mr. E. W. Lycett, 

 manager of the Borax Consolidated Company's calcining 

 works. 



Between Ascotan and the coast at Antofagasta lie vast 

 volcanic areas and the nitrate belt. Only one river which 

 might support fish occurs — the Loa. But at Calama ( ele- 

 vation 7,000 feet) it was found to be totally devod of them. 

 This is reported to be due to a water fall twenty-five 

 kilometers downstream, below which coastal forms exist. 



Xo new genera of fish were obtained in the Titicaca- 

 Poopo drainage system. Only two genera, Orestias and 

 Pygidium, occur. There is probably sufficient material 

 collected for adjusting the very unsatisfactory status of 

 the species. 



It is hoped that the parasites of the fishes may, through 

 their affinities, throw some additional light upon the 

 origm of the fauna of the land-locked Titicaca-Poopo 

 system. With one exception few jDarasites were obtained 

 from the many hundreds of fish dissected. The one ex- 

 ception was a miimte, active trematode resident in the 

 cranical cavity of nearly eveiy Orestias examined, but 

 not occurring in Pygidium. It is found not only in Titi- 

 caca itself but in all the tributary lakes and streams. 



In the lakes of the altiplane the great quantity of bird 

 life in the broad plant zone of the littoral is noteworthy. 

 There are many coots, cormorants, grebes, ducks, flamin- 

 goes, ibises, lapwings, and gulls. The writer estimated 

 that there were not fewer than 10,000 wading birds per 



