With certain fixatives the spiral structure of chromosomes was clearly observed practically throughout all the stages from the late prophase of heterotype division up to the formation of the tetrad nuclei. In the interkinesis no anastomoses take place between chromosomes, but each individual coiled chromosomes can be clearly traced throughout the stage. In young tetrad nuclei chromosomes present the same coiled appearance as those found in the interkinesis. The double spiral of the heterotype metaphasic chromosomes as described by other authors was not observed in this plant, but it seems to be highly possible that an appropriate method of treatment will disclose the same nature of the spiral in the heterotype metaphase in the sweet-pea too.
(1) In the triploid wheat hybrids (A)×(A+B), Triticum dicoccum _??_+×T. monococcum _??_ and T. aegilopoides boeoticum, _??_×T. dicoccum _??_, we have found various modifications of the normal chromosome combination (7II+ 7I), for instance, 3 trivalent chromosomes, which consist of the union of 3 bivalents and 3 univalents. The number of trivalents varies from 0 to 3 (Table 2). In some cases there is a tetrapartite chromosome (not tetravalent). (2) In the tetraploid hybrid (A)×(A+B+D) between T. spelta and T. aegilopoides boeoticum. 0-3 trivalents and 0-3 bivalents from autosyndesis of chromosomes of B- and D-sets besides 7 normal bivalents were observed (Tab. 3). The tetraploid hybrid was weakly fertile (Tab. 4). (3) We saw the normal chromosome combination 14II+7I in nearly all the cases of T. durum×T. vulgare (A+B)×(A+B+D), and 1-2 trivalents rarely (Tab. 5). (4) The relationship among the chromosomes of 3 different sets, A, B and D, may be given as follows;_??_ A-3-B means that 3 chromosomes from A- and B-sets have affinity to conjugate.