PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 11 



grains form au exceedingly well-defined one-layered stratum which 

 is restricted to the ectoplasm alone. 



"Entz has discovered that he could cause colorless Infusoria to be- 

 come green by feeding them with green palmellaceous cells, which, 

 moreover, did not die after the death of their hosts, but continued to 

 live, growing and developing within the latter until their total evolution 

 proved them to be forms of very simple microscopic green algai, such 

 as FalmeUa, Glceocystis, &c. (E. P. Wright.) * * * There may be 

 parasites such as observed by Dr. Entz. but. judging from their super- 

 ficial position [in V. chlorostigma], their glohnluT form, and behavior to- 

 wards reagents, the absence of a nucleus, or of any cleavage stages, 

 they must, it seems to me, be regarded as integTal parts of the creatures 

 in which they are found." 



The above the writer quotes from a paper published by him two years 

 since in Forest and Stream, and later in Bull. U. S. Fish Conrm., I, 411, 

 and in the interim no facts have been brought to his notice which have 

 tended to shake his faith in the soundness of this view. 



It is true that there are certain Infusorians in which a bottle-green 

 tint is difi:use and not confined to distinct grains, as, for instance, in 

 StentorMiiUeri and Freia 2)i'odiicta, both of which the writer has studied. 

 but in IStentor polymorphus and the green species of Oplirydium the color 

 is confined to distinct granules, as in the species of VorticeUa which I 

 have figured. The uncolored species of Ojihrydium, found in Frank- 

 ford Creek, and which has been named 0. adw by Everts, does not dif- 

 fer much in other respects from its congeners, but the colorless Stentor 

 Baseli does differ considerably in form and details of habit from its 

 allies. These are facts which, it seems to me, are almost fatal to the 

 theory of the existence of green parasitic vegetable forms in Infusorians, 

 the only facts favorable to the idea that the green color is due to 

 algous parasites being those noted of Ophrydium, a genus which affords 

 an instance of green and colorless forms, differing otherwise but slightly. 

 In fact, individual zooids of Ophrydium are sometimes met with which 

 are only partly green, or have only one-half the body colored, while 

 alongside of them in the same colony individuals are found which are 

 wholly green. Then, again, how are the so-called red and dark-colored 

 Stentors to be disposed of, both of which have been detected in the 

 United States ? For these, indeed, it may be claimed that degenerating 

 chlorophyll would be capable of producing the red color of the first. 

 and that feeding on very dark colored alg;e might develop the latter. 

 In spite of all this, however, there remains a residuum of facts which 

 cannot be disposed of on any the^ ry of symbiosis or parasitism, and 

 this is especially the case with these forms which, as in Stentor. show 

 three distinct types of coloration, viz, the diffuse bottle-green, that 

 caused by colored green granules, and the colorless : all of these tliffer- 

 ences at the same time being indicative, together with other features, 

 of very distinct species. 



