46 University of California Publications in Zoology [Vol. 13 



Stein (1858, 1859, 1861, and 1867) followed with short but excel- 

 lent descriptions. Although lacking illustrations, Stein's work was 

 good ; he gave model descriptions and a scientific classification. He 

 described the genera Opliryoscolex, Entodinium and Isotricha. In 

 1861 he added to his earlier work, and again in 1867. In this later 

 work he classifies for the first time the genera Opliryoscolex and 

 Entodinium under the family name Ophryoscolecidae. 



In 1869 Weiss confirmed the presence of these infusorians in the 

 stomachs of ruminants and contented himself principally with a report 

 upon the writings of Delafond and Stein. 



Leuckart (1879-1886) only reviewed the researches of Stein. 



In 1872 Ziirn did a large amount of work, but owing to poor 

 technique his material was bad, and consequently his descriptions 

 were faulty and his figures inaccurate. In a second edition of his 

 work (Ziirn and Plant, 1887-1889), he abandoned his earlier figures 

 and enlarged upon his descriptions by quoting from Schuberg's (1888) 

 discoveries. 



Kent (1881) published, in his Manual of the Infusoria, a com- 

 pilation of the work of Stein (1858, 1859, and 1861), but this com- 

 pilation contained many errors. Kent, as a matter of fact, added 

 nothing along this line to the work of his predecessors. 



List (1885) gave little that was new. The animals over which he 

 worked were either dead or had been affected by the water. His 

 work, in so far as it relates to the ciliates, is without present value. 



In 1888 Schuberg published the results of his work on Buetschlia, 

 Isotricha, Dasytricha, and Entodinium. His work was the most scien- 

 tific and most complete done up to his time and in some respects is 

 still the best. He described two new genera, which he named 

 Buetschlia (with two species) and Dasytricha (with one species). He 

 added several species to Stein's genus Entodinium and divided the 

 genus into two genera, i.e., Entodinium and Diplodinium, although he 

 gives neither a description nor an illustration of the genus Diplo- 

 dinium — in fact nothing beyond the mere statement that the genus 

 Diplodinium is provided with two sets of membranelles, one around 

 the mouth opening and the other on the dorsal side. His methods 

 he describes in detail and to these we shall have occasion to refer 

 later. He intended to write a second lengthy paper, but never, so 

 far as I am able to determine, was this published. In 1891 he pub- 

 lished a short paper, which contains no illustrations and is occupied 

 largely with a description of some of the structural relationships and 



