314 DR. T. GOODEY OX 



('11) gives the dimensions of Bodo saltans as 6-10 p in lengtli by 

 3-5 fx in breadth. My organism is much smaller than this, 

 measuring from 5-6 yu in length by 2*5-4 fx in breadth. In this 

 respect it comes nearest to Bodo miimmos Klebs, which is from 

 4-5 /x in length and is considered to be one of the smallest 

 flagellates. The latter form, according to its origina,l describer, 

 is changeable in shape and has a creeping movement. My 

 organism is very constant in shape, and always moves in i-apid 

 jumps followed by intervals of rest. There can be no doubt, then, 

 that its specific name should be saltans. 



Alexeieff ('11, p. 508) says that, without a doubt, Bodo saltans is 

 the same organism sls ProtvazeJcia parva described by Ntigler ("10). 

 The latter organism differs considerably from that described above 

 in several respects. Its protoplast is labile and takes on a gi'eat 

 variety of shapes, whereas my organism is constantly bean-sliaped. 

 The method of division in both the tropho- and kinetonucleus is 

 quite different from that described above. There is no frag- 

 mentation of the karyosome of the trophonucleus with the 

 ultimate formation of four chromatin granules or' chi'omosomes, 

 but merely an equal division of the karyosome by promitosis, a 

 centriole and a centrodesmose taking part in the process. The 

 kinetonucleus divides in a similar manner. It is obvious, there- 

 fore, that Nagler's organism is a species distinct from mine, and 

 his name ProivazeJcia parva should be allowed to remain. 



Among the descriptions of members of the genus ProioazeMa 

 by Hartmann & Ohagas ('10), Niigler ('11), Mathis & Leger ('10), 

 Withmore ('H), Martin ('13), and Belai- ('14), the division of the 

 trophonucleus of Prowazekia asiatica by Withmore comes nearest 

 to that which I have given in the foregoing account. His figs. 18 

 and 19 show the presence of four principal chromosomes in the 

 dividing nucleus, which, however, diflTers considerably in its 

 earlier division stages from those observed in my organism. 



(2) Tetramitus spiralis, sp. n. (Pis. II., III., figs. 23-45.) 

 (a) Structure. 



This interesting organism occurred in cultures from three 

 different soils, viz. : Agdell 1867, Broadbalk 1865, and Barn- 

 field 1870. I have been fortunate in obtaining it in large 

 lunnbei's, and have been able to make out most of the details 

 of its structure and mode of division. I have not, however, 

 observed it in the encysted condition, although I kept my 

 cultures for a long time and had the organisms under close 

 observation in hanging drops. I will first describe its structure 

 and movements, and then deal with the process of reproduction. 



In the majority of cases the body is pyriform in shape, having 

 its extreme anterior end somewhat pointed. It may, however, 

 become nuich elongated, and then appears more cylindrical. 



A groove runs spirally from the anterior to the posterior end 



