80 SPIROCELETES. 



the gastric epithelium. It attains a length of 130^ and 

 a breath of 3 to 4^. It is said by Keysselitz, to have a 

 flattened form and either sharp or blunt extremities 

 (Figs. 61, 62, 620). Those with sharp ends show peri- 

 plastic appendages (periplastfortstaze). The periplast 

 is fibrillary in appearance, and there is a granule (basal- 

 korn) at each end and an undulating membrane. The 

 nuclear chromatin takes the form of balls, irregular 

 masses and elongated bands; it may collect in a single 

 strand toward the centre of the organism. Keysselitz 



FIG. 61. Spi'-ochseta spiculifera. (Schellack.) 



did not observe a spiral arrangement like that described 

 by Perrin in Sp. balbianii, but admits that such may 

 exist. Division is by longitudinal fission. 



Schellack notes that the border fibre of the undulat- 

 ing membrane is of variable thickness, tapering toward 

 the end, unlike that of trypanosomes, and believes that 

 it is not a true membrane, but an artifact due to sepa- 

 ration of periplast. I am inclined to agree with this 

 view, as I find that the better the preparation is fixed 

 the fewer organisms appear with this formation (see 

 page 20). The nucleus, according to Schellack, consists 

 of a series of bands, not of a spiral, and the whole 



