LEE BARKER WALTON HI 



viding to approximately, a 16-ceIl stage, small flagellate 

 gametes emerge and conjugate. An experiment of this 

 nature involves a discussion of the environmental effect 

 on germ cells as compared with somatic cells, but does 

 not affect the issues with which we are concerned in the 

 present paper. 



There are many other questions of interest which arise 

 in a study such as outlined. For instance, what has been 

 the origin of the stride which are much specialized in many 

 forms, although entirely absent in other forms so far as 

 visibility with the microscope is concerned. The majority 

 of the positive northern forms have "left-handed" strias, 

 a smaller number have longitudinal striae, while a con- 

 siderable number appear to have no striae. None have 

 been found with "right-handed" striae. At first one may 

 be inclined to attribute such a character to natural selec- 

 tion, but when one commences to ascertain the value of 

 the character on the basis of progression, rotation and 

 axial angle, such a conclusion seems less certain. There 

 are a few facts that appear evident. First that the 

 development of the striae has been at a considerably later 

 period than that of the rotation direction. Second that 

 the relative position of the striae has been largely depend- 

 ent on the rotation. Third, that the development of the 

 striae has in many forms proceeded so far that a reversal 

 rotation seems an impossibility. 



The presence of a considerable number of other groups 

 which have "left-handed" spirals so far as observation 

 goes, is of interest. The various genera of Spirochaetes, as 

 well as Spirul'ma and Arthrospira among the Cyaiwphy- 

 coidea (Cyanopbycece) may be mentioned. The twining 

 of plants may, in the final analysis, be attributable to the 

 same cause. 



Other related problems are the pendulation theory of 

 Simroth (1912) relative to bipolar distribution, and the 

 tropism theory as outlined by Verworn (1894), in con- 

 nection with the excitation contraction of the flagellum. 



