Inequality of the two Eyes in regenerating Planarians. 



79 



VI. In another series of five worms oblique decapitation was 

 immediately followed by removal of along strip from the shorter 

 lateral edge (Fig, K). The axis became sharply concaved, toward 

 the cut side. In four of the five cases the outside eye was larger, 

 in the other case the two eyes were equal. 



It is a noteworthy fact that in Series VI, in which the two cuts 

 were made in such a way that nearly all the excised material came 

 from one side of the animal, the disparity in size of eyes was much 

 more marked than in Series IV and V, in which the proportion of 

 the material excised from the side opposite that whence the long 

 lateral strip was removed was greater than in the cases of Series VI. 

 It is unfortunate that time limitations under which this work was 

 done did not admit of repeating the three series of experiments last 

 described (IV, V and VI) for the purpose of getting data from a 

 larger number of individuals. As the matter stands, the results are 

 suggestive, not conclusive. 



The main results of all the experiments are summarized in the 

 following table. 



d 



œ 



13 

 CG 



m 

 'S 



Nature of operations 



0) 



O 



03 



O) in 

 03 



03 be 



•-• CO 

 t« — 1 



Is 



03 



m 



03 



(^ 



f3 

 _cS 



-Ö 

 03 03 



<- 03 

 03 



-g 



>i o 



IS 



IIa 

 Hb 



Ilia 

 . lUb 



IV 



V 



VI 



6 



1 

 10 



21) 



17 



9'^) 



5 



5 

 5 



Projecting lateral slip (Fig. B) 



Detached lateral slip? 



Oblique decapitation 



Oblique decapitation and, 7 days later, 



excision of strip from longer side (Fig. E) 



Oblique decapitation 



Oblique decapitation 



10 days later, excision of strip from longer side 



7 days later, first cut repeated 



Oblique decapitation and immediate 



excision of strip from longer side (Fig. H) 



Transverse decapitation and immediate 



excision of strip from one side (Fig. J) 



Oblique decapitation and immediate 



excision of strip from shorter side (Fig. K) 



6 

 1 

 5 



2^) 

 9 



6 



2 

 2 

 4 



3 



4 



1 



1 

 1 



2 

 4 



1 



2 

 1 



1 



2 



Totals 



60 



37 1 



10 



10 1 1 



2 





Percent 



62—1 



16+ 



16+ 



5 





1) Two individuals of the ten of IIa. 



2) Reversal of proportions of eyes in two individuals of IIa. 



3) Nine individuals of the seventeen of Ilia. 



These experiments indicate, first, that fragments of Flanaria 

 maculata which are unsymmetrical with reference to the original 



