8 ANNIE PORTER 



It may be mentioned here that Schellack (1900) lias recently 

 stated that in S. halhianii there is a terminal tuft of flagella. 

 Although I hâve examined many spécimens of S. halhianii alive 

 and under natural conditions as far as possible, I must say that 

 I hâve never seen such tufts of flagella. Fiirther, I hâve not 

 seen them in stained préparations. I fear that thèse appearan- 

 ces are due to rupture or fraying of the ends of thc organism and 

 its membrane. 



IV. — Movements. 



The movements of progression of 8. halhianii and 8. anodon- 



tae bave been very thoroughly described by Fantham (1907-8), 



^gjt^%^ and he bas also 



^gg/f^^-omma^^ ^^V '^ depicted some of 



€ "^^^ j the striking « pat- 



^^ ^^ terns » that Spi- 



FiG. 2. Represents a spirochaete vibrating about a central node rOChaetCS fomi 

 which acts as a pivot. 



when movmg. 

 Fantham (I. 1908, p. 17) states that the ordinary or usual 

 motion of a Spirochaete may be resolved « into at least two 

 f actors or components : ( 1 ) an undulatory flexion of the body, 

 mainly for progression, and (ii) a spiral or corkscrew move- 

 ment of the body as a whole, due to the winding of the mem- 

 brane. )) 



Other striking movements frequently performed by the 

 Spirochaetes of Lamellibranchs may now be mentioned. 

 Spécimens of 8. anodontae. sometimes are seen describing a 

 circular movement. The middle of the parasite, forming a node, 

 seems to act as a centre of rotation or pivot about which 

 the two parts of the parasite move circularly (fig. 2, node). 

 The direction of rotation is usually from right to left and is 

 very rapid. There was no thickening or thinning at the centre 

 of the parasite, whose circular movements ceased after a time, 



