SYNOPSIS OF THE ROTATORIA. 



By Harry K. Harring, 



OJ the United States Bureau of Standards, Washington, D. C. 



INTRODUCTION. 



It has almost become established practice to preface every con- 

 tribution to the knowledge of the Rotatoria with a complaint against 

 the inextricable nomenclature. When the writer started work on 

 the group some years ago, and as a preliminary step catalogued the 

 known species, it was found that nearly all the necessary literature 

 was on file in Washington libraries. This requisite being at hand, 

 it seemed that by going over the entire class and bringing Rotatorian 

 nomenclature into agreement with the International Code, the 

 much-needed zoological revision of smaller groups would be greatly 

 facilitated. No pretense is made here to alleviate the zoological 

 difficulties, except in so far as this may be done by determining the 

 types of the genera now in use or proposed in the past. 



Names proposed for units of less than specific rank have as a rule 

 been thrown into synonymy. Usually such names have been intro- 

 duced for bionomic, ethologic, seasonal, or periodic variants; as 

 these are not at present recognized in zoological nomenclature, no 

 other course seemed open. A definite term for such forms is desirable, 

 and as Semenov ^ has recently proposed the designation "morpha" 

 for these, it would be well to adopt it, with the explicit understanding 

 that, while written in Latin form, it is to be disregarded nomen- 

 clatoriaily, so that even though a unit originally proposed as a 

 "morpha" should later prove of specific value, its "morpha" name 

 should not be accorded priority. This is suggested because it is 

 likely that a number of such names may be required, and numerous 

 intergradations are probable, and it might be difficult, if not impossi- 

 ble, to determine which one had priority. These variants are not 

 subspecies as this term is now understood. All the evidence up to 

 the present indicates a remarkable constancy of specific characters; 

 wherever a rotifer is found it is morphologically identical with repre- 



1 A. Semenov Tian-Shansky, Die taxonomischeu Grenzen der Art und ihrer Unterabteilungen. Ver- 

 suche einer genauen Definition der untersteu systematischen Kategorien. Berlin, 1910. 



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