CHAPTER XVIII 



SPECIES OF STENTOR 



Brief histories of our knowledge of the kinds of stentor are 

 included in Kent's Manual of the Infusoria (1881) and in Johnson's 

 monumental study of the genus (1893). The first recorded observa- 

 tions of the group were made by Abraham Trembley of Hydra 

 fame. In a letter to the Royal Society of London (1744) he 

 described "funnel-like polypes" of green, blue, and white types 

 which would correspond to the present species called polymorphus, 

 coeruleus, and roeseli or muelleri. Feeding, with both rejection and 

 retention of particles he noted. Division was correctly described 

 as being oblique and this was confirmed somewhat later with much 

 surprise by Packard (1937). The present 5. roeseli was included in 

 Linnaeus' Sy sterna Naturce, tenth edition of 1767, under the 

 name of Hydra stentorea. Stentors were later clearly differentiated 

 from hydras and the first use of the generic title Stentor for this 

 group was made by Oken in his Lehrbuch der Naturgeschichte^ 

 1815. 



Oken's genus was not taxonomically accurate, for it included 

 vorticellids and rotifers and did not consistently use the binomial 

 nomenclature. Nevertheless, to retain a well-known name, the 

 genus Stentor Oken 181 5 was recently validated at the instigation 

 of Kirby (1956), whose account of the generic term is here 

 summarized. It is well that this was done because at one time the 

 name had been suggested for a group of howler monkeys. S. 

 muelleri was chosen as the type species since it was the first species 

 adequately described and figured, by Ehrenberg in 1831. 



Descriptions of the more common and better known species 

 coeruleus and polymorphus have already acquainted the reader with 

 the general morphology of this genus. The most outstanding 

 features in common are the trumpet shape from which the group 

 derives its name, conspicuous contractility throughout the length 

 of the body, longitudinal rows of cilia throughout, attachment by 



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