OKLAHOMA ACADEMY OF SCIENCE 59 



acter and the others give twice as many females as the red-black 

 females and 3 non-spotted males again: The 2:1 ratio is obtained 

 from the addition of a 1 :1 and a 3:1 ratio because as before the 

 males may be either heterozygous or homozygous. 



The nearest result is that we have two separate recessive 

 genes for red-black and black-red located in separate chromosome 

 pairs. Different pairs of homologous chromosomes would act as 

 duplicate genes. If these reversals should prove to be a result of 

 crossing over it would be approximately 33 1-3 percent. 



Another method is that of incomplete dominance. Here the 

 dextral and sinistral unilateral traits would appear according to 

 1 :1 ratio, instead of 2:1 ratio. Incomplete dominance would of nec- 

 essity occur only when the organism is heterozygous for red spots 

 and black spots. 



VIII. THE EFFECT OF HYDROXIDES ON THE 



FISSION RATE OF PARAMOECIUM 



Dixie Young 



From the Zoological Laboratory of the University of 

 Oklahcma, Ccntr.'bution No. 34, Second Series. 



Comparatively little is known of the factors which under- 

 lie growth as expressed by the reproduction of cells, but the more 

 we know of the methods by which it can be modified, the nearer we 

 shall be to the solution of the problem. Paramoeciiim lends itself 

 favorably to a study of division rate since it consists of a single 

 cell. In a single celled animal are eliminated some of the complica- 

 tions which must be dealt with in higher forms, where effects 

 may vary with varying tissues, and where the complexity of the 

 animal renders the results more difficult of interpretation. The 

 usuallj'- short interval between generations, and the ease with 

 which "pedigree" lines may be established also make the protozoon 

 well adapted for experimental work. The investigations of such 

 workers as Calkins and Woodruff have established the value of 

 the'rate of cell divsiion in infusoria as an indication of the general 

 physiological condition, and this is ordinarily accepted as a basis 

 on which to determine the metabolic acitvity. The present study 

 was undertaken with the object of extending some of the observa- 

 tions made by Richards on the effects of certain hydroxides on 

 the rate of division in the eggs of Haminea virescens. It appeared 

 of value to the problem to determine the results when the hydrox- 

 ides are used to stimulate different protoplasm. 



All of the experimental lines used in this work were started 

 from a single paramoecium which was taken from a mass culture 



