South American Rotifer a. By J. Murray. 231 



In all the groups of Rotifera, tlie known species are so numerous 

 that only a specialist can identify them. This may seem unfor- 

 tunate for the naturalist pure and simple, the pond-life man, but 

 it is not so if we recognize the different roles of the naturalist and 

 the systematist. If a man simply takes a delight in observing his 

 Eotifers, and cannot find time to make himself a specialist, it does 

 not really matter to him to have them accurately named. The 

 trouble arises when men who do not even profess to be specialists 

 publish faunistic lists without notes or figures. 



So much confusion has arisen from inaccurate original diagnosis 

 of new species, followed by slipshod identification, that it is safe 

 to say that the greater proportion of lists of Rotifers, unaccompanied 

 by figures, have no value whatever. This evil should be greatly 

 diminished if the Rotifera were standardized in a series of mono- 

 graphs in which all the species of each family or group were 

 figured to the same scale. 



Meanwhile the conscientious systematist.. if he wishes his work 

 to have any value, has no alternative but to figure most of the species 

 observed. You know then what he means by his names, and if 

 he makes a misidentifi cation, no harm is done. It is for this reason 

 that I here figure every species of the family Cathypnidae which 

 occurs in my South American collections. 



As in every paper which I write upon the Rotifera, I must here 

 express my thanks to Mr. Rousselet for his assistance and advice. 

 He placed freely at my disposal his immense collection of Rotifera 

 and his extensive library of Rotifer-literature. He was always 

 ready to advise me about critical species. Moreover, he himself 

 first found many of the species in my collection, mounted them, 

 and handed them over to me. Without all this help it would have 

 been quite impossible for me to get up in a comparatively short 

 time a sufficient knowledge of many of the families to enable me 

 to make identifications with confidence that I was not adding to 

 the confusion amonsj the Rotifera. 



As the paper is a fairly large one, and requires a great number 

 of figures, it has been divided into three parts for convenience in 

 publication. From this arises a difficulty in dealing with the 

 Bibliography. A single bibliography at the end would have been 

 most satisfactory, but the bibliographical material for the later 

 sections of the paper cannot be ready in final form when this first 

 section goes to press, and so I see no practicable plan but to give 

 a bibliography with each section. 



In Chile Rotifera were collected in three localities : ponds in 

 the principal square of Antofagasta ; a pond at Viiia del Mar, near 

 Valparaiso ; and at Punta Arenas, in the Straits of Magellan. In 

 the last-named locality many ponds were netted, and much moss 

 collected on the hills. 



In Argentina the Rotifera were obtained from one pond in the 



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