468 E. ELEANOR CAROTHERS 



derived from the mother, shows a constriction near the end to 

 which the fiber attaches in both parent and offspring. This is 

 a condition which I have noted before ('17) as running through 

 the complexes of given individuals. The only objection to the 

 use of this characteristic as a tag is that it is not always apparent 

 in individuals where it potentially exists. 3) Chromosome num- 

 ber 8 was telomitic in both parents and in the offspring. 



b. Mating number 13 {pi. 1, row 5 cf parent, row 6 9 parent, row 

 7 cf offspring). The chief interest in this mating as already 

 stated Hes in chromosome number 1. In the father both homo- 

 logues are atelomitic, in the mother telomitic, so that the off- 

 spring would be expected to be heteromorphic, if there is no re- 

 organization. That such is the case may be seen in row 7. 

 Chromosome number 7 is atelomitic in both parents and offspring 

 and chromosome number 8 is telomitic in all three. 



c. Mating nuinber 5 {pi. 2, row 8 cf parent, row 9 9 parent, 

 rows 10-14 cf progeny). Seven male offspring were studied. All 

 had similar chromosomal constitutions. First spermatocyte com- 

 plexes of five of these are shown on the plate. Both parents 

 have the three pairs of chromosomes under consideration in the 

 condition in which they most frequently recur in the species, 

 but if the chromosomes of their progeny vary according to their 

 range in the species the other conditions might appear, e.g., 

 chromosome number 1, which is telomitic in the parents, ought, 

 if its telomitic and atelomitic phases follow their frequency of 

 occurrence in the species, to have given two atelomitic dyads 

 among the fourteen contained in these seven individuals, since 

 we have seen that the ratio among the wild individuals is 1 to 7. 

 Likewise, one out of every nine homologues of pair number 8 

 should have been atelomitic and one out of seven dyads of pair 

 number 7 should have been telomitic. In no cases was there 

 a change from the type of chromosome transmitted by the 

 parents. To be sure, the number of individuals is small, but 

 when we consider that the expectations would have been about 

 two variations for each of the three pairs or six chances the 

 evidence decidedly favors the alternative hypothesis of constancy 

 of form. (As has been mentioned before, chromosome 7, row 



