84 BOTANICAL GAZETTE [JANUARY 
A new interpretation of mitosis——In 1911 DEHORNE published two papers’ 
setting forth a new interpretation for the phenomena of somatic and hetero- 
typic mitosis in animals and plants. According to this author, the units usually 
called chromosomes are in all stages of all divisions associated in pairs, each 
pair having the value of a longitudinally split single chromosome. At meta- 
phase they are not divided along this split, but are simply separated into two 
groups which pass toward opposite poles. During anaphase the members of 
each pair separate somewhat from each other and become secondarily split. 
After persisting through the resting stages as interlaced spiral threads, these 
two double structures are finally separated at the next metaphase. Thus the 
line of separation at any metaphase is determined during the second preceding 
anaphase. The diakinetic pairs are in like manner regarded as longitudinally 
. split somatic chromosomes. At the first maturation division one-half of these 
pairs goes to each pole, bringing about a reduction. During anaphase each 
member is longitudinally split as in the somatic mitoses. At the second division 
instead of separating into their longitudinal halves, they are distributed in two 
groups of double rods. According to this interpretation the haploid number of 
chromosomes in Lilium should be regarded as 6 and the diploid number as 12, 
rather than 12 and 24. 
G 4 in a very detailed description of the metaphase and anaphase 
in Galtonia, Trillium, and Allium, demonstrates clearly that in every case 4 
dicentric separation of the halves of each chromosome occurs, and that there 
is no such pairing as DEHORNE has described. In a second short note’ he 
shows, after a careful study of Lilium, that the phenomena of maturation fol- 
low the heterohomeotypic scheme previously described by him, and contradict 
in all points the conclusions of DEHORNE. What is true of Lilium is held by 
GrécorrE to be generally true of all higher plants and many animals. These 
results, together with those of MUCKERMANN" on Salamandra and other forms, 
are conclusive in showing that the interpretation of DEHORNE is wholly false.— 
L. W. SHARP. 
- 
%B siaevcseeioa: A, , Recherches ss la division de la cellule. I. Le duplicisme con- 
stant du chr alamandra maculosa Lour. et chez Allium ae 
L. Archiv f. Zelforschung es i ie pls. 35, 36. figs. 2. 1911; Recherches su 
division de la cell II. Homéotypie et hétérotypie chez les Annélides poly: chet 
et les wecutec ae Zool. Exp. et Gén. 9: 1911. 
4 Grécorre, V., Les phénoménes de la métaphase et de anaphase dans la cary 
cinése somatique. A propos d’une interprétation nouvelle. Annales Soc. Sci. Bruxelles 
34:pp. 36. pl. I. 1912. 
15 , La vérité du schéma hétérohoméotypique. Compt. Rend. 155: 1098- 
II00. 1912. 
16 MUCKERMANN, H., Zur Anordnung, Trennung, und Polwanderung der Chromo- 
somen in der Metaphase und Anaphase der somatischen Karyokinese be bei Urodelen. 
La Cellule 28: 233-252. pls. 2. 1912. 
