TRANSACTIONS Of SECTION K. 779 



Ike chromosomes thicken and reach maturity before their arrangement on the 

 spindle. There the well-known fission reasserts itself, and results in the forma- 

 tion of the groups of chromosomes of the pair of daughter nuclei. Now, precisely 

 similar conditions obtain during the early prophase of the heterotype mitosis 

 in Galtonia. Neither in the somatic nor in the meiotic prophases is there a 

 definitely numerical estimation of chromosomes possible: The number of separate 

 chromatic structures is quite variable. The longitudinal fission in the heterotypc 

 is prepared for, as in the preceding mitoses, during the telophase of the last 

 archesporial division, and on the reconstitution of the chromosomes in the early 

 heterotype prophase, exactly similar paired arrangements are to be discerned 

 as in a somatic mitosis. Finally the nucleus goes into synapsis; and here it 

 must be admitted that it is not possible to follow exactly what occurs, but sub- 

 sequent events show that at any rate there is at that stage no pairing of 

 individual or homologous chromosomes. In the hollow spireme which follows, 

 more or less definite traces of the preceding longitudinal fission can still be 

 seen, and it may be mentioned in passing that there is some variation in the 

 way in which the process as a whole is conducted. Sometimes the thread looks 

 uniform, at other times threads made up of distinctly double filaments are to 

 be seen. There is considerable anastomosis between the thread work at this 

 stage, and the same is true of certain other plants in a still higher degree. 

 Moreover, there is a considerable range of variation in the thickness of the 

 threads — or thread-pairs — in the same nucleus. This is of weight, as much 

 stress has been laid on thickness as a criterion cf structure. A full account of 

 these structural features will be published shortly. As second contraction comes 

 on, the loops and tangles of the spireme become more closely appressed, and a 

 paired arrangement quickly becomes obvious. The whole process is rapidly gone 

 through, and there seems to be a wide range of variation in the actual manner of 

 approximation. Thus sometimes a bending over of a loop, at other times the 

 approximation of distinct chromosomes to each other takes place. There may be 

 a twisting round each other or a merely parallel arrangement. 



It is easier to follow out the process in Galtonia than in many other plants, 

 owing to the remarkable difference of size which exists amongst the chromosomes 

 themselves. 



The later stages call for no particular comment, but we desire to call special 

 attention to this plant as one in which there can be no mistake in the seriation. 

 We have for some years selected Galtonia for detailed observation, owing to the 

 advantage, already alluded to, of the absence of any intercalated phrase of ' rest ' 

 between the last archesporial and the heterotype mitosis. We feel convinced that 

 the same interpretation to be placed on the events of prophase in the ordinary 

 archesporial prophase, must also apply to the corresponding stage of the hetero- 

 type, and that, as was said some years ago, the union of somatic chromosomes 

 to form the pseudochromosomes, and their separation at the heterotype mitosis, 

 is to be regarded as a stage intercalated between the prophasic longitudinal 

 fission of the heterotype and the completion of this fission, which is thus post- 

 poned to the homotype division. We would point out that those who hold the 

 other view have never explained why there should invariably be two mitoses 

 comprised in the meiotic phase. 



3. On the Vermiform Male Nuclei of Lilium. 

 By Professor V. H. Blackman, M.A. 



The shape and structure of there nuclei were described in detail, and circum- 

 stantial evidence brought forward that these structures, though purely nuclear 

 in nature, are capable of movement, and make their way by their own activity 

 into the egg-cell and towards the polar nuclei. 



4. Colour Inheritance in Anagallis anensis, L. 

 By Professor F. E. Weiss, D.Sc. 



The scarlet and blue pimpernels, regarded by some botanists as different 

 Bpeciea — Anagallis arvensis, L., and A. carulca (Shreb) respectively — are united 



