1. The two independent inversions In (X) Sp and In (X) Sd found in the X-chromosome of D. virilis, when existing together in the heterozygous state, increase the crossing over in the terminal regions of the third and fifth chromosomes and that in the proximal region of the third chromosome.
2. They also increase the crossing over in the terminal region of the X-chromosome itself.
3. The distal inversion existing singly also increases the crossing over in the terminal region of the third chromosome, but not that in the terminal region of the X-chromosome.
4. The proximal inversion existing singly has no effect on the crossing over in the terminal region of either the third or the X-chromosome.
5. The degree in which an inversion affects the crossing over in other chromosome or in other region of the same chromosome, depends on the degree of suppression caused by the inversion of the crossing over in its adjacent region.
6. The effect is of the same nature as that of high temperature or of X-ray radiation: an increase in one region of the chromosome is always accompanied by a decrease in the other. This ‘competitive’ (Mather) or ‘compensatory’ (Kikkawa) relation is due to the existence of the upper limit in the number of chiasmata formed in the same nucleus.

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1. Die Larve der Luciola lateralis ist an ihrem vorletzten Abdominalsegment mit einem paarigen Leuchtorgan versehen, welches aus einer spurenweisen Uratzellschicht, die als Refraktor dient, und einer hauptsächlichen Leuchtzellschicht, welche keine Tracheenendzellen besitzt, besteht. Die Leuchtzellen enthalten Granula, welche sowohl nach wiederholtem Aufblinken als auch nach längerem Verlöschen in Größe, Zahl und Anordnung keine Veränderung zeigen.
2. Das Leuchtorgan der Larve zeigt keine rhythmischen monophasischen Potentialschwankungen als bioelektrische Außerung des Aufblinkens. Die einzelnen Potentiaischwankungen, die je von verschiedener Dauer sind, erfolgen je kontinuierlich und sind von Ruhepausen gleichfalls von verschiedener Dauer unterbrochen.
3. Das Männchen der Imago der Luciola lateralis besitzt am vorletzten und am letzten Abdominalsegment an deren ventralen Fläche je ein Leuchtorgan, während das Weibchen an der ventralen Fläche des drittletzten Abdominalsegments nur ein Leuchtorgan hat. Das Leuchtorgan besteht aus einer ventralen Leuchtzellschicht, welche stellenweise sternförmige Tracheenendzellen mit Reduktionsfähigkeit enthält, und einer dorsalen Uratzellschicht. Die Leuchtzellen enthalten Granula, welche zu jeder beliebigen Zeit, gleichviel ob nach wiederholtem Aufblinken während längerer Zeit oder nach längerem Verlöschen, in Zahl, Größe und Anordnung immer konstant bleiben. Jede einzelne Trachee dringt in eine Tracheenendzelle mit 3-4 in verschiedenen Richtungen ausstrahlenden Fortsätzen hinein, um dort ihre Spiralen zu verlieren und sick in 3-4 Tracheenkapillaren zu teilen, welche in die Fortsätze hineindringen. Nach Einatmung von Osumiumsäuregas erfolgt eine Schwärzung dieser Zellen, die auf einer Ablagerung der Körnchen des metallischen Osmiums beruht, auf welches die Osmiumsäure in diesen Zellen reduziert wird.
4. Am Leuchtorgan der Imago der Luciola lateralis erfolgen als bioelektrische Begleiterscheinung des periodischen Aufleuchtens rhythmische monophasische Potentialschwankungen, welche Häufungen und zwar nicht selten Bigeminie bzw. Trigeminie aufweisen; hinter je mehreren dicht aufeinanderfolgenden Potentialschwankungen tritt eine kurze Ruhepause ein.
5. Die vergleichende histologische und elektrophysiologische Beobachtung legt die Annahme nahe, daß die Tracheenendzellen bei der Sauerstoffzufuhr regulatorisch funktionieren. Durch die Reduktionsfähigkeit der Tracheenendzellen wird der in die Tracheen eingeatmete Sauerstoff ihnen rhythmisch durch diese Zellen entzogen, um eine rhythmische Unterbrechung der Sauerstoffzufuhr in die Leuchtzellen zu bedingen. Dies wird zur Ursache einer periodischen Einstellung der Verbrennung der Leuchtsubstanz, wodurch wiederum ein rhythmisches Verlöschen eintritt. Diese Annahme wird durch die Tatsache gestützt, daß am Leuchtorgan der Larve von Luciola lateralis, in weichem noch keine Tracheenendzellen entwickelt sind, sich keine rhythmischen Aufblinken erkennen lassen.

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1. Bei der Larve von Luciola cruciata und von Pyrocoelia rufa erfolgt das Leuchten nicht rhythmisch, sondern kontinuierlich, ohne dicht aufeinanderfolgende kurzdauernde Aufblinken. Beim Leuchten lassen sich von dem Leuchtorgan Aktionsströme als monophasische Potentialschwankungen ableiten. Die einzelnen kontinuierlichen Potentialschwankungen sind von verschiedener Dauer und werden von Ruhepausen von verschiedener Dauer unterbrochen.
2. Das Leuchtorgan der Larve von Luciola cruciata und von Pyrocoelia rufa besteht ebenso wie das der Imago aus einer Leuchtzell- und einer Uratzellschicht. Beim Leuchtorgan der Larve von Luciola cruciata entwickelt sich die Uratzellschicht nur spurenweise, bisweilen sogar kann sie schwer naehgewiesen werden. Die Leuchtzellen bei beiden Larven enthalten in ihrem Zytoplasma lückenlos prall gedrängte Granula, welche mit Eisenhämatoxylin nach HEIDENHAIN besonders gut färbbar sind. Die Größe, Zahl und Verteilung dieser Granula sind, gleichviel oh sie nach langer Leuchttötigkeit oder nach langem Verlöschen des Leuchtorgans beobachtet werden, immer konstant. In der Leuchtzellschicht lassen sich bei beiden Larven nirgendwo Tracheenendzellen mit Reduktionsfähigkeit erkennen. Man könnte also die nicht rhythmisch auftretenden Aktionsströme des Leuchtorgans auf das Nichtvorhandensein dieser Tracheenendzellen, die als rhythmischer Regulator der Oxydation der Leuchtsubstanz dienen, zurückführen.

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1. Ebenso wie bei anderen Leuchtkäfern besteht das Leuchtorgan der Luciola cruciata aus einer Leuchtzellschicht und einer Uratzellschicht. In der Leuchtzellschicht sind Eisenhämatoxylin nach HEIDENHAIN besonders gern aufnehmende feine Granula prall gedrängt enthalten, während in den Uratzellen Konkretionen von harnsaurem Ammoniak vorgefunden werden. Nach Einatmung von Osmiumsäuregas lassen sich überall in der Leuchtzellschicht sternförmige, mit 3-4 Fortsätzen versehene Tracheenendzellen erkennen, welche regellose Anordnung aufweisen. Diese Fortsätze verlaufen zwischen den Leuchtzellen, ohne Anastomosen zu bilden oder in die Leuchtzellen einzudringen.
2. Eine Teilung der Tracheenstämmchen in 3-4 Tracheenkapillaren erfolgt in den Tracheenendzellen, nachdem sie ihre Spiralen verloren haben. Die Kapillaren dringen in die 3-4 Tracheenendzellenfortsätze, welche zugespitzt sind oder plötzlich abreissen, hinein und können in ihnen noch eine Strecke lang verfolgt werden. Die Osmiumreduktion erfolgt nur in den Tracheenendzellen mit ihren Fortsätzen, während sie in den Leuchtzellen mit Ausnahme der den Tracheenendzellen anliegenden Teile der Leuchtzellen nicht stattfindet.
3. Bei Luciola cruciata spielen die mit Reduktionsfähigkeit begabten Tracheenendzellen die Rolle eines Regulators der rhythmischen Sauerstoffzufuhr in die Leuchtzellen und also der Verbrennung der Leuchtsubstanz, was ein rhythmisches Verlöschen des Leuchtorgans bedingt.

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1) The bivalent in Trillium takes usually a cruciferous form, the pair of paired chromatids being associated only by the kinetochores themselves. This condition of pairing has been regarded by the chiasmatheorists as representing one chiasma or two localized at the vicinity of the kinetochore. In the present study, the paired kinetochores were strictly distinguished from chiasmata and were not counted as the latter in recording. It was pointed out then that earlier workers of the chiasma shool disregarded this point making their data on chiasmata seriously unreliable.
2) Based on this new method, the present study was made on the comparison of the frequency of metaphase chiasmata in one control plant (t₀) with those in four other plants (t₁-t₄) which had been subjected to high temperature prior to metaphase.
3) The mean chiasma frequencies per cell in these plants were found to be: t₀, 0.45, t₁ 1.49, t₂, 2.20, t₃ 4.31, t₄ 6.53. Such great increases in chiasma frequency have not been reported before. In terms of the chiasma school, this change in the situation is from “localized chiasmata” to “random chiasmata”
4) There are two types of bivalents distinguishable as to the pairing condition of the kinetochores that is, (i) “K-bivalents” where the kinetochores of the homologues remain paired until metaphase and chiasmata may or not be formed, (ii) “k-bivalents” where the kinetochores are unpaired at metaphase and chiasmata are alone responsible for the maintenance as bivalents. In t₀-t₃, the bivalents are nearly almost of the former type, while in t₄ they are of the latter type in a majority of cases.
5) In K-bivalents, the frequency of interstitial chiasmata is a function of arm length, while in k-bivalents it is a function of entire chromosome length (see Graphs 1 & 2). It was also found that the k condition of the kinetochores is correlated to certain extent with an increase in the frequency of interstitial chiasmata and furthermore greatly with the occurrence of univalents.
6) The above principles about interstitial chiasmata were found not to hold true as they stand to terminal ones. In the present material, terminal chiasmata are negligibly low in frequency. In general, however, they occur more frequently in plalnts in which interstitial chiasmata are higher in frequency. It is also significant that terminal chiasmata occur in relatively higher frequencies at the nucleolar forming ends of the chromosomes, that is, at both the ends of A and the end of the short arm of E. It was inferred from these findings that the chromosome matrix acts as the prime factor for the maintenance of terminal chiasmata and the nucleolus plays a subsidiary rôle for it.
7) The present findings are at variance with the view of the chiasma school that the formation of random chiasmata is the sign of complete pairing. With respect to the paired or non-paired condition of the kinetochores (K and k respectively) and the formation or non-formation of chiasmata (C and c respectively), it was concluded that the typical or standard bivalent is represented by the Kc condition, and KC and kC types of bivalents are its derivatives (see Fig. 12).
8) The above view favors the two-plane theory of chiasma formation, that is, chiasmata are formed by the alternate opening-out of sister and non-sister chromatids at diplotene and therefore not related in their origin to crossing-over. It was then assumed that such alternate opening-out is due to the development of two or more points of repulsion in an arm, a condition of rather unusual nature in contrast with the normal case, where the repulsion force initiates at its one point (probably the distal end);

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1. Campanuleae has about 31 genera, of which 12 have been studied cytologically and their meiotic chromosome numbers were counted by the writer.
The genera and number of species studied by the writer are as follows:2. Campanulinae has about 12 genera, 7 of which have been studied cytologically by the writer; namely Campanula, Symphyandra, Adenophora, Specularia, Michauxia, Trachelium and Phyteuma. The chromosome number 17 seems to be the universal one, because the majority of genera in the Campanulinae has 17 or its multiples. From the previous karyological results the diversity in chromosome numbers is only found in Campanula and Phyteuma where 8 and 17 are found in the former and 18, 13, 12, 17, 5 in the latter.
3. The genus Campanula has two groups whose chromosome numbers are different; viz. 8 and 17. While the multiples of 17 are abundantly found, those of 8 are rather rare. To date the meiotic chromosome number 16 has been only found by Gairdner (1926) in C. persicifolia “Telham Beauty” and by de Vilmorin and Simonet (1927) in C. isophylla.
From the following considerations these two groups seem to have been derived quite independently of each other:
a) If the n=17 group had been derived from the n=8, the former would have larger epidermal cells than those of the latter. But in reality, the epidermal cells of the leaves of the former are smaller than those of the latter.
b) The n=8 group has generally linear lanceolate stem-leaves, and up to this time we have not found other than linear lanceolate leaves in the plants having the meiotic chromosome number 8.
c) We do not find any similarity in the outer appearances between n=17 and n=16 groups, but we find it among plants having 8 or its multiple chromosomes and also among plants having 17 or its multiples.
d) It is very interesting that there are no 8 groups in Adenophora, Symphyandra etc., though they are systematically very closely allied to Campanula.
These facts show that we cannot say that 17, which is universally found in Campanulinae is derived from 8. On the contrary, the 8 group can be said to be independent of Campanula having n=17.
4. Wahlenbergiinae has about 16 genera, of which 4 had been studied cytologically and their meiotic chromosome numbers were counted.
5. Platicodinae has only one genus. Our cytological observations show that it is probably of hybrid nature.

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1. Genetical and cytological studies on ten translocations and four inversions found in D. virilis have been carried out. All the translocations are of the mutual type.
2. The recombination values between the genes located in the vicinity of the loci at which the chromosomes are broken or reattached, are lower than the corresponding standard values.
3. The loci of many genes determined by means of these chromosomal aberrations are illustrated in Plate 1.
4. The loci of the spindle fiber attachment have been determined for all the chromosomes including the second and the fourth for which no genetical data are available.
5. The chromocentral region of D. virilis is not a mere aggregate of the proximal ends of the chromosomes, but is composed of very conspicuous granular element-the α-heterochromatin.
6. The β-heterochromatin exists at the proximal end of all the chromosomes, except the third and the sixth.
7. The α-heterochromatin represents the inert regions of the mitotic chromosomes including the Y chromosome, while the β-heterochromatin represents the active genes occurring in the inert regions.
8. The nucleolus is not connected with the β-heterochromatin in the X chromosome, but it is connected with the α-heterochromatin by a bundle of spiral threads.
9. The morphologically ‘weak’ points found in the euchromatic region seem to have no genetical significance. The existence of some genetically weak points is assumed on the ground that the breakages in chromosome aberrations have a tendency to fall at some definite loci, and crossing over often takes place at a particular space on the sixth chromosome.
10. The fusion of the distal ends of the salivary gland chromosomes frequently observed in the smeared preparations, is no more than a random gathering. Studies on the sections of the salivary glands show that all the distal ends of the chromosomes are separate.

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1. By treatment with 0.08% colchicine solution in 20 hours at 25°C tetraploid plants were induced in 2-5% of the treated seeds in 3 species: Linum usitatissimum, L. angustifolium and L. crepitans.
2. These tetraploid plants were of gigas types having tall stems and thick leaves. Size of pollen grains, flowers, capsules as well as seeds were also larger than those of the diploid plants. Retardation of growth in comparison with the diploids was usually observed.
3. In tetraploids the mean fertility of pollen grains was 60-70% in value, however, the number of seed set was considerably smaller amounting 2-10%, mainly because many flowers dropped down before capsules developed.
4. Chromosome behaviour was also examined. The configuration, 4_IV+22_II was commonly found at the 1st metaphase in L. crepitans. In anaphase, lagging chromosomes were frequently observed. Unequal distribution of chromosomes were suggested from the counting of them at the second metaphase.

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1. The seeds of Melandrium album were treated with a 0.04% aquaous solution of colchicine, a part of them for 5 days and the rest for 10 days. Five per cent of seedlings from the 5-days and 12.5 per cent from. the 10-days treatment samples were found to be mixoploid consisting of 2X and 4X cells.
2. These mixoploids were mostly sectorial chimerae, so that manner of distributions of the 2X and 4X tissues were various and there were observed, though rarely, very complicated intermingling of those two kinds of cells between rather pure 2X and 4X tissues.
2X-and 4X-flowers are different from each other in their sizes, but not in their shapes, while the shape of the flowers having intermingled cells vas different from those with 2X- or 4X-cells.
Sometimes 2X- and 4X-PMCs appeared intermingled in one and the same sporangium and they behaved themselves as in the non-intermingled sporangium. Regular tetrad formation occurred in those 2X-PMCs, while in the 4X-PMCs the irregular behaviours of the quadrivalents caused the formation of several irregular pollen grains, including sterile ones. These behaviours will be the chief cause of the fact that the di-tetramixoploid plants gave much more 2X-offsprings than 4X or 3X ones.
3. The mixoploidy can not be considered as affecting the length of the juvenile period. The latter is probably due to special genes. The mixoploid plants bloomed a little later than the diploid plants having same kind of genes.
4. The epidermis seems to play a role on the determination of the organs so far as their size is concerned.
Here the writer wishes to express her hearty thanks to Prof. K. Fujii for his kind advise in the course of the investigation. The writer's best thanks are also due to the Japan Society for the Advancement of Cytology by a grant from which this work was made possible.

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A diploid karyotype heterozygous for three chromosome pairs is newly described (Karyotype 2n-V). Nucleolar conditions were investigated in five diploid and in two triploid karyotypes. D-type chromosomes are nucleolar, developing a nucleolus interstitially at the region of satellite stalk in the case provided with a satellite (chromosome D and D-₁) and terminally at the naked distal end of the short arm in chromosome D-which is deprived of its whole satellite. In accord with the number of nucleolar chromosomes contained the maximum number of nucleoli in the root-tip nuclei is two in diploids and three in triploids irrespective of the karyotypic alterations.
The writer wishes to acknowledge his sincere gratitude to Professor H. Matsuura for his valuable suggestion and criticism and for his kindness in taking the photomicrographs reproduced in the present paper. The expence of carrying out the present study was partly defrayed out of a grant from the Science Research Fund of the Department of Education to which his thanks are also due.

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1. Das imaginale Leuchtorgan der Pyrocoelia analis sowie der Luciola Gorhami besteht ebenso wie bei anderen Spezies von Leuchtkäfern aus einer ventralen Schicht von Leuchtzellen, welche dicht gehäuft sog. Leuchtgranula enthalten, und einer dorsalen Schicht von Uratzellen, welche Konkretionen von harnsaurem Ammoniak enthalten. Die Granula nehmen mit Vorliebe Eisenhämatoxylin nach HEIDENHAIN auf und bleiben in Gräße, Form und Verteilung immer konstant.
2. In der Leuchtzellschicht des imaginalen Leuchtorgans der obigen tropischen Spezies lassen sich überall hie und da regellos zerstreut ange-ordnete sternförmige mit 3-4 Fortsätzen versehene Tracheenendzellen erkennen, in welche die einzelnen Tracheenstämmchen hineindringen, um sich dort in 3-4 Tracheenkapillaren zu teilen. Diese Kapillaren verlaufen, ohne an Länge die Fortsätze zu übertreffen, in diesen zwischen den Leuchtzellen verfließenden Fortsätzen eine Strecke lang und endigen dann plötzlich oder wie abgerissen. Der Bau und die Verteilung der Tracheen-endzellen zeigen nicht das für die meisten tropischen Leuchtköfer charakteristische Bild und erinnern vielmehr an dasjenige bei verschiedenen subtropischen Leuchtkäfern in Japan.
3. Die Struktur des larvalen Leuchtorgans der Pyrocoelia analis ist mit Ausnahme des Fehlens der Tracheenendzellen prinzipiell dieselben wie beim imaginalen Leuchtorgan, indem es aus einer Konkretionen von harnsaurem Ammoniak enthaltenden, dünnden dorsalen Uratzellschicht und einer sog. Leuchtgranula enthaltenden dicken ventralen Leuchtzellschicht besteht. Die Uratzellschicht bedeckt die Leuchtzell-schicht von medial dorsal mützenförmig. Der Charakter der Leuchtgranula im larvalen Leuchtorgan ist gleich dem im imaginalen Leuchtorgan

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