• Volume 8, Issue 1

      July 1938,   pages  1-78

    • A study of the chromosome number in some Indian members of the familyCodoniaceae

      P N Mehra

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      1. The chromosome numbers in three Indian speciesFossombronia himalayensis Kash.,Petalophyllum indicum Kash. andSewardiella tuberifera Kash. have been investigated. The diploid chromosome number in each case is 18 but the morphology of the chromosomes in each species is different from the other.

      2. The basic chromosome number in the familyCodoniaceæ appears to be 9.

      3. Polyploidy is of rather rare occurrence in the evolution of new species in the family.

    • Abnormal sporocarps inMarsilea minuta linn

      P N Mehra

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    • Heterochromatin, somatic “crossing-over” and the interchange hypothesis between non-homologous chromosomes

      Dontcho Kostoff

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    • Studies in the proteaceae - II. Floral anatomy and morphology of Macadamia ternifolia F. Muell.

      S B Kausik

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      The vascular anatomy of the flower shows that the perianth inMacadamia ternifolia F. Muell. is the whorl of sepals, while the corolla has completely disappeared. Thus a dichalmydeous ancestry is suggested for the Proteaceæ. The adnation of the stamens to the perianth is of recent origin.

      The nature of the carpel is discussed in the light of the interpretation of Hunt (1937) regarding the origin of the modern Angiospermic carpel.

      The structure of the anther is described. The pollen grains contain a tube nucleus and a small generative cell at the shedding stage.

      The nature and development of the ovule are pointed out. The embryosac develops along normal lines.

      Fertilization and changes in the ovule after fertilization are described. The nature of endosperm, some stages in the development of the embryo and the parts of the mature seed are dealt with.

      Several instances of degenerations of ovules and one instance of an abnormal ovule with two nucelli and common inner and outer integuments are recorded.

    • Studies on the caudal autotomy and regeneration inMabuya dissimilis hallowell

      S M Sibtain

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      The following résumé brings together the more important features discovered during the course of this work:

      1. The lepidosis of the regenerated tail differs from that of the normal in the fewer number of scale rows and in the presence of the enlarged m d-dorsals in addition to the enlarged mid-ventrals. The normal tail is not segmented externally in correspondence to autotomy planes.

      2. The regenerated tail is lighter-coloured (i.e., more or less pinkish in appearance) and is poor in melanophores.

      3. The general arrangement of the tissues in the tail ofMabuya is similar to that described forHemidactylus, but the subcutaneous fat-layer is entirely absent.

      4. The dermal scutes show inter-connecting bridges and thus go to form an extensive body armour. This feature has not been so far noted by previous authors.

      5. The regenerated tail has also sixteen muscle bundles like the normal.

      6. The cartilaginous tube in the regenerated tail inMabuya does not show any distinction between a central (uncalcified) and a peripheral (calcified) portion, as discovered inHemidactalus.

      7. The cartilaginous tube has occasional large perforations.

      8. The contents of the cartilaginous tube show histologically a similarity to bone-marrow, and do not show any pigment cells.

      9. The sacral vertebræ inMabuya are fused together to form a synasacrum. The anterior two caudal vertebræ have no chevron bones. The inter-central articulations between the caudal vertebrae are inseparable on account of strong ligamentous unions, and the vertebrae are divided by an autotomy plane, which is neither cartilaginous nor hyaline.

      10. The muscle processes are arranged in two lateral series, each consisting of four.

      11. Each autotomy segment is telescoped into the one behind it. There is nodistinct autotomy septum inMabuya as in other lizards—there being only a clear split in the osseous tissue of the vertebrae concerned.

      12. The breaking of the regenerated tail into pieces by vigorous pulling indicates that the caudal muscles here also are arranged in a “dove-tailing” manner. The number of muscle bundles is the same as that found in the normal tail.

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