534 r. OIJFFORI) DOBKLL. 



parasitic in Lamellibrauclis, (2) the iiiucli smaller pai-asitic 

 organisms like " S pi roc li 03 1 a '' pallidii, ''• S . " buccalis, 

 the organisms of relapsing fevers^ etc., (o) the free-living 

 forms Spirochasta plicatilis and its allies. 



Now the name Spiroclifeta^ was introduced by ]!^hrenberg 

 in 1833 for the free-living organism S. plicatilis. It must 

 therefore be applied to this and similar organisms. The 

 structure of S. plicatilis has been described by Schaudinii 

 (1905, 1907). According to liim there is an undulating 

 membrane and a nucleus in the form of a lorjgitudinal 

 filament surrounded by chromidia — these two elements corre- 

 sponding respectively to the kinetic and trophic nuclei of a 

 trvpanosome. Reproduction occurs by multiple transverse 

 fission. 



Quite recently these organisms have been more carefully 

 studied by Zlilzer (1910), whose observations differ greatly 

 from those of Schaudinn. She interprets the axial filament 

 as an elastic body — not part of the nucleus. The latter is 

 represented by large, regularly arranged chromatin granules. 

 There is no undulating membrane. If this description is 

 correct,- it is obvious that S. plicatilis is a very different 

 organism from Cristispira. Anyone who has observed 

 living specimens of S. plicatilis would, I should think, be 

 impressed by their dissimilarity to Cristispiras — both as 

 ]-egards movements and general appearance. This, at all 

 events, is my own impression. The bodies of both are flexible 

 and spirally wound, but beyond this there is no great resem- 

 blance. The differences are at least sufficiently great to 

 justify the bestowal of different generic names upon the two 

 organisms. As Gross has introduced the name Cristispira 

 for the mollusc Spirochtets it should henceforth be adopted. 



The smaller parasitic Spirocha3ts — such as the syphilis 



' The correct spellint;' of this n;iiiie is Spirocluvta . and not Spiro- 

 chaite, as adopted liy Dofiein (1!>0!J) and nmnerous other writers. 



" I have every reason to believe it is, as I had an opportunity of con- 

 versing with Frl. Dr. Ziilzer and seeing some of her preparations at the 

 International Zoolo<rical Congress in Graz this year (1910). 



