1. Statistically significant differences were found among nineteen plants of Lolium peieuee L. in total number of chiasmata, number of terminal chiasmata, and number of open bivalents per microsporocyte. The chiasma frequency was not correlated with the terminalization coefficient.2. The percentage of metaphase I sporocytes showing univalents varied from zero to 9.7 in the different plants. The range in percentage of metaphase I sporocytes showing non-orientated bivalent and loosely attached bivalents was 1.3 to 14.8 percent and 1.0 to 32.0 percent, respectively.3. Statistically significant negative correlation coefficients were obtained (1) between total chiasma frequency and percentage of metaphase I sporocytes having univalents and (2) between both total and terminal chiasma frequency and percentage of sporocytes having loosely attached bivalents. Percentage of sporocytes with non-orientated bivalents was not correlated with chiasma frequency. The terminalization coefficient was not correlated with metaphase I univalents. non-orientated bivalents, or loosely attached bivalents.4. In one plant, CT 405, 41.6 percent of the anaphase I sporo-cytes had one or more lagging univalents, a maximum of six occurring in one sporocyte. In the remaining plants, the percentage of sporocytes showing laggards varied from zero to 2.5. The lagging univalents divided equationally in all observed cases.5. The percentages of metaphase I sporocytes with univalents and with loosely attached bivalents were correlated with frequency of lagging univalents at anaphase I when the data for CT 405 were not included in the calculations. Apparently most of the laggards in this plant arose from some source other than these two.6. The numbers of chromosomes were determined in the two groups at anaphase I in 633 sporocytes in which lagging chromosomes did not occur and in all cases seven chromosomes were seen in each group.7. The data on frequency of micronuclei in the sporocytes at interphase I indicated that a majority of the daughter half chromosomes from anaphase I laggards were included in the daughter nuclei.8. The percentage of quartets with one or more micronuclei in one or more of the four cells ranged from zero to 30.0 percent in eighteen plants. Apparently lagging and dividing univalents at anaphase I were important in producing micronuclei in the quartets both as a result of failure of the daughter half chromosomes to reach the poles in the first division and their inability to move normally in the second division.9. In ten of the plants, the number of micronuclei per 100 quartets varied from 26.7 to 71.4 percent of the expected number calculated on the assumption that all daughter half chromosomes from anaphase I laggards formed micronuclei. No micronuclei were expected in one plant and none was obtained. In the remaining six plants, the number of micronuclei exceeded the calculated. One plant had about three times as many as expected. These results suggested that micronuclei were produced in certain plants from some source in addition to lagging univalents at anaphase I.10. This conclusion was supported by the occurrence in seven plants of types of quartets, based on number and position of micronuclei, which were not expected on the assumption that all micronuclei were formed from daughter half chromosomes derived from lagging and dividing univalents at anaphase I.11. The presence of dicentric bridges and acentric fragments at anaphase I, interphase I, and in the quartets indicated that thirteen of the nineteen plants were heterozygous for inversions.12. Rare aneuplofd sporocytes in one plant and a tetr aploid sporocyte in another plant suggested occasional irregularities in premeiotic divisions.13. Percentage of normal appearing pollen varied from 21.2 to 95.7 percent in eleven plants.