528 V. CLIFFOKD l»()l]KLL. 



l)raiie which bound the protoplasm of the body ; but such 

 inembraiies are found in the majority of Protista, only they 

 are not usually called " periplasts." I shall therefore avoid 

 using this term, as I believe it leads to a confusion of ideas; 

 and I shall speak of the cuticular covering of a Cristispira 

 as the "^"^ cell membrane," or simply as " the membrane." 



A membrane certainly exists in CristispirM. Unless this 

 were present, it is difficult to see how the contours of the 

 body ai-e preserved. The appearance of bnrst individuals 

 also indicates that a membrane of some sort is present (see 

 fig. 3). Moreover, the presence of a membrane is cleaidy 

 demonstrated when the organisms undergo plasmolysis. This 

 has been clearly shown by Swellengrebel (1909) in C. bal- 

 bianii. 



It has frequently been stated that the " periplast " of 

 Cristispira possesses a fibrillar structure, which can be 

 seen when the organisms are macerated. I have seen many 

 individuals of C. veneris which show the appearances which 

 have been thus interpreted, and I believe tlie fibi-ils are 

 derived in all cases from the crista (see fig. 3). The cell- 

 membrane itself possesses no structure. Schellack (1909) 

 states that "bei den grossen SpirochaetenMst ein fibrillarer 

 Periplast siclier nachgewieseu; er kann kiinstlich aufgefasert 

 werden." I believe this is incorrect. M}^ own view is the 

 same as that expressed by Gross — "Der Periplast existirt gar 

 nicht. Die Cristispiren haben einfach eine ziendich starke, 

 aber farberisch nicht differenzirbare Zellmembran." As 

 Gross has discussed the matter fully I will say nothing 

 further about it — mere!}- pointing out thaC my interpretation 

 agrees with his. 



The Crista. — Schellack (1909) interprets the crista as 

 an artifact — " als ein durch kitnstliche Veranderung des 

 Periplasts hervorgerufenes Gebilde." I believe this inter- 

 pretation to be quite incorrect. The crista is easily visible in 

 slowly moving, living oi-ganisms, and is constantly present in 

 properly fixed specimens. It is homogeneous and possesses 

 ^ I.e. Cristispira^. 



