U NOTES ET REVUE 



Ihis second flagellum caiiuot be seen in the case of many individuals. 

 Not only tliat, but I hâve a few heavily stained préparations, in which 

 the long flagellum happens to be much more intensely stained than in 

 either of the préparations from which figs. 1 and 2 were draAvn, and yet 

 in not a single individual can the accessory flagellum be seen. As stated 

 above, therefore, this second flagellum is not constantly présent, and in 

 some races or strains appears to be altogether absent. 



The accessory flagellum lias a very definite orientation with regard 

 to the body. When the Flagellate is gliding, the trailling flagellum 

 aiways lies uppermost, and we may adopt the convention that, in this 

 position, it is dorsal to the body. The small flagellum has its origin very 

 clos? to that of the long one ; there is a well-marked blepharoplastic 

 thickening at the point of origin, but it is difficult to be certain whether 

 there is a single large blepharoplast, or two in contact with each other. 

 The accessory flagellum aiways projects slightly upwards (dorsally) 

 and somewhat to the right side, ne ver to the left. In life, it is best 

 caught sight of as the créât are swings slightly to and fro, about the axis 

 of the trailing flagellum. As the Flagellate swings to the left, and the 

 long flagellum passes a little to the right, the accessory flagellum projects 

 outwards on that side, from the anterior end. In this position, its slow, 

 waving motion can be observed. The fact that it is curved and not 

 altogether in one plane adds to the difiîculty of detecting it. Owing 

 to its delicacy, at one focus its distal extremity only may be seen, appear- 

 ing as a short rod or dot, travelling parallel to, but separate from the 

 body. When at rest, this short flagellum is usually directed somewhat 

 backwards, terminating about on a line wdth the middle of the nucleus. 

 Occasionally, however, it projects straight outwards, at right angles 

 to the long flagellum ; in such a case, when the créature is lying in the 

 true dorsi-ventral plane, the small flagellum gives a straighter, hardei- 

 outline to the anterior end of the body (fig. 2). The length of this acces- 

 sory flagellum varies from about lu to 1 1/2 u. 



The présence of this accessory flagellum does not throw any light 

 upon the peculiar gliding movement of Helkesimastix ; because it is 

 often held stiff and motionless while the créature is gliding forwards. 

 It remaiiis uncertain, in fact, what can be its function. It does not 

 waft food-particles into the mouth, because there is no mouth ; and we 

 hâve never seen any indication of vacuolar ingestion and digestion of 

 food, as occurs, for instance, in Monas. If Helkesimastix does ingest 



