606 DESCBIPTION OF [Rotatoria. 



Mr. Howard has proposed the name Anneloida, to include the 

 Rotatoria, Annelida, JEchinodet-mata, and Trematoda, y/hich. he thinks 

 form a natural group of annals. 



The reader is referred for an account of the structure, and of 

 other matters I'elating to the Rotatoria generally, to the several 

 sections devoted to their consideration in Part I. In the following 

 systematic account of these animals, the text of the first edition is 

 generally followed, and consequently the description of the organi- 

 zation is in accordance with that given by Ehrenberg in his great 

 work of 1838. More recent investigations, indeed, have brought 

 into doubt some of the views entertained by Ehrenberg concerning 

 the structure of Rotatoria, but still the present amount of knowledge 

 on this point is not sufiiciently extended and precise to warrant its 

 employment to the exclusion of the matter supplied by the great 

 naturalist of Berlin. 



The reader must therefore bear in mind that Ehrenberg's hypo- 

 theses of organization colour the majority of the ensuing generic 

 and specific description, whilst the general account of Rotatoria in 

 Part I., represents the opinions of the structure and functions of 

 particular organs entertained by others as opposed to those held by 

 Ehrenberg. To a right understanding of this systematic description 

 of the Rotatoria, the reader should be familiarly acquainted with the 

 details of structure and function given in Part I., and then he may, 

 if he pleases, read the description of organs, according to recent 

 views of their function, in place of those advanced by Ehrenberg. 

 Thus, when male vesicles, sexual glands, transverse vessels, respi- 

 ratory tubes, &c., are spoken of, it would be remembered that others 

 prefer to call the first named circulatory organs ; the second, simply 

 glands ; the third, transverse or circular muscles ; and the fourth, 

 a solid process, or rudimentary antennae. 



Family.— ICHTHYDINA. 



Rotatoria with a single continuous rotatory organ, not cut or 

 lobed at the margin. They are destitute of lorica or shell. In 

 Ptyyura and Glenophora the wheel-like organ is in the form of a 

 circle, and serves for the purposes of locomotion; in the other 



