BY WILLIAM A. HASWELL. \99 



The Rhabdocffile hosts appeared to be in full vigour and activity, 

 notwithstanding the hundreds of the parasites in incessant move- 

 ment in the cells. But in one instance the cell containing the 

 parasite contained also a number of actively-moving Vibriones, 

 so that in some cases at least a destructive effect would appear to 

 be produced. 



The relationship of the parasite to the Euglenoids is unmistak- 

 able ; and it bears a considerable resemblance to Euglena deses, 

 Ehr., the young of which is described as devoid of flagellum and 

 moving by peristaltic contractions.* But no member of this 

 family, or, so far as I can ascertain, any other group of Flagellata, 

 has ever been observed living as an iutra-cellular parasite. Pfeiffer 

 in a recent work, "Die Protozoan als Krankheitserreger,"! states : 

 " Aus Klasse I., die Infusorien und Flagellaten umfassend, sind 

 obligate Zellschmarotzer unter den parasitisch lebenden Species 

 noch nicht bekannt." But as far as the Flagellata are concerned, 

 the statement would still be correct were the word "obligate" 

 omitted. Several cases of parasitic Flagellata are mentioned by 

 BvitschliJ ; but these occur in the mucus of various organs, such 

 as the alimentary canal, opening on the exterior, and, in the case 

 of Trypanosoma and Herpetomonas, in the blood § ; none of them 

 inhabit the interior of cells. I think the observation now recorded 

 is of some importance as suggesting a different origin for some at 

 least of the SjJorozoa than that suggested by Ray Lankester. || 



* Saville Kent, "Manual of the Infusoria," p. 383, pi. xx. figs. 52 and 53. 

 t I am indebted to Professor J. T. Wilson for directing my attention to 

 this work. 



X " Protozoa " of Bronn's ' Thier-Reich,' p. 868. 



§ Lewis, 'Q. J. Micro. Sci.,' Vol. xxiv. (1884). 



11 Zoological Articles from the ' Encyclopaedia Britannica,' "Protozoa," p. 26. 



