453 



true Trypanoplasma is still I believe an open question, vid. (M. Kuhn, 

 Die Trypanoplasmen und deren Verbreitung in einheimischen und aus- 

 ländischen Schnecken. Sehr. Phys.-ökonom. Ges. Königsberg. III. 

 p. 63 — 89. 1911). In the Quarterly Journal of Microscopical Science 

 Vol 55, 1910, I published an account of the division of what I regard 

 as a true Trypanoplasma from the stomach of a conger, and in this di- 

 vision although I found a fairly complete series I could find no evidence 

 for the view that the division of the kinetonucleus is a mitotic one. In 

 a forthcoming paper I hope to deal with the division of the other two 

 flagellates from the stomach of fishes which have been described as Try- 

 panoplasmas, and in both of these cases again, although I do not regard 

 these forms as Trypanoplasmas , I have not been able to find any evi- 

 dence of a mitotic division of the kinetonucleus. From the work of 

 Rosenbusch and Jollos it would appear that the chief difficulty in 

 seeing the spindle in the dividing kinetonucleus depends largely on the 

 compact nature of the kinetonucleus and its intense capacity for nuclear 

 stains. I had long wished to find some form with a more vacuolar kineto- 

 nucleus , and such a form I believe I have found in some cultures of a 

 sick soil the opportunity of studying which I owe to the kindness of 

 Doctor Rüssel, of Rothamsted. I have decided provisionally to de- 

 scribe this animal under the name of Prowaxekia terricola. 



Though it seems to differ rather markedly from all the Proivaxekia 

 that I have found in my cultures in the fact that during movement the 

 two flagella as far as could be observed are constantly directed forwards. 

 At rest both flagella may be directed backward across the body. 



Proivaxekia terricola in life is a more or less spindle-shaped organism 

 measuring, roughly, 12 by 6«, with two flagella arising near its anterior 

 end. Near the base of the flagella there is a small contractile vacuole 

 and a not too well marked cytostome. In life the trophonucleus can be 

 made out as a rather large vacuolar area containing a distinct karyo- 

 some. This flagellate is rather an active form, moving with a curious 

 wriggling motion with both flagella directed forwards. In stained forms 

 the two flagella can be seen to arise from as far as I could make out 

 two closely approximated blepharoplastic granules lying near the an- 

 terior end of the body. Lying constantly posterior to these granules there 

 is a large vacuolar structure which stains intensely with nuclear stains 

 This structure having regard to its position and to its behavior in divi- 

 sion I am inclined to regard as a kinetonucleus. The kinetonucleus is 

 somewhat variable in structure but as a rule it presents the appearance 

 of a more or less elliptical vacuole containing a number of darkly 

 staining granules. The trophonucleus is a rather large spherical struc- 

 ture containing a rather lightly staining karyosome and with a number 



