The Spermatogenesis of Hvurid Peas 533 



have spores whicli miglit be of pure descent or might not be so 

 according to the manner of the orientation of the segments in the 

 metaphase of the first division. The chromosomes might be as- 

 sociated and distributed by chance as I have recognized (Cannon, i) 

 and as Sutton has dwelt on at length.* What the connection of 

 the chance distribution of the chromosomes may be with the 

 distribution of the characters among the hybrids is not at all 

 clear, since the relation of the chromosomes to the characters 

 is not known, but the cytologist has abiding faith that there 

 is some connection which will be demonstrable with the micro- 

 scope, and he looks to the field of hybrids and of hybridization as 

 a new opportunity for experimentation by which to supplement 

 and to substantiate the results of his studies. Experimentation 

 and cytological studies on hybrid forms in which the number of 

 chromosomes is known and in which the number of characters 

 has been determined should show a connection, if there is one, 

 between the number of characters that are transmissible and the 

 number of the chromosomes and their morphology. I wish here 

 to call attention to what very likely is merely a chance coinci- 

 dence, but nevertheless suggestive and interesting, namely, to the 

 agreement in the number of the groups of constant differentiating 

 characters as given by Mendel for the peas used by him in ex- 

 periments with the reduced number of chromosomes in the peas. 

 As given by Bateson (Bateson, i), the characters are (a) differences 

 in the length and color of the stem ; (d) in the size and form of the 

 leaves; (r) in the position, color and size of the flowers ; (c/) in 

 the length of the flower-stalk ; (i-) in the color, form and size of 

 the pods ; (/) in the form and size of the seeds ; (^) in the color 

 of the seed-coats and cotyledons. In the peas there are evidently 

 more appreciable characters than chromosomes, and therefore the 

 chromosomes bear more than one character each. If then the 

 chromosomes maintain their individuality certain characters might 

 be associated together in the same chromosome, and might be 



borne in mind, however, that a difficulty in drawing conclusions at present from the 

 results of Rosenberg's studies of the sporogeny of the Drosera hybrid may lie in the 

 partial sterility of the form. (See Focke, Ptlanzenmischlinge, 155.) Further work 

 on this hybrid is promised and will be awaited with interest. 



* Sutton, W. S. The chromosomes in heredity. Biol. Bull. 4: 231. 1903. 



