• Volume 60, Issue 1

      July 1964,   pages  1-80

    • A physico-chemical analysis of ripe, unspawned eggs of some freshwater teleosts

      Rehan Hasan A K Jafri

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      An analysis of some physical as well as chemical aspects of ripe eggs belonging to 19 species of freshwater fish has been made.

      Apart from the colour, eggs of closely related species resemble each other in their specific gravity, diameter and chemical composition.

      Protein, fat and phosphorus content is always higher as compared to muscle.

      Moisture content is usually less than 63% and decreases with the increase of fat in various species. A higher or lower fat content does not in any way affect the time required for embryonic development and hatching.

      Calcium and iron are lower in comparison to the muscle.

    • Effect of superparasitism inBracon gelechiae Ashmead

      M J Chacko

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      1. WhenBracon gelechiae is multiplied in the laboratory on the larvae ofCorcyra cephalonica a high incidence of superparasitism occurs.

      2. Superparasitism has an adverse effect on the fecundity and longevity of this parasite.

      3. The competition among the developing parasites for the available amount of food is the factor that inhibits the development of the parasites into normal forms, when superparasitism occurs.

      4. There is no marked increase or decrease in fecundity or longevity in successive generations, whether or not the development is normal.

      5. When superparasitism occurs, all the parasite grubs on a host do not complete larval development; others that apparently complete larval development do not spin a cocoon; some that succeed in pupating do not emerge, while rarely some emerge as ‘runts’.

      6. Superparasitism is accompanied by a preponderance of males.

      7. Superparasitism has a direct bearing on the developmental period. As the number of parasities that develop on a host increases the developmental period also increases.

      8. Although dwarf forms are produced as a result of superparasitism, this is not a general effect inBracon gelechiae.

      9. It is suggested that superparasitism should be avoided as far as possible in the laboratory breeding of this parasite.

    • Palynological studies in some non-commercial citrus varieties

      V S Motial

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      1. The shape of pollen grains in all the varieties excepting Sadaphal was prolate spheroidal, while in Sadaphal it was prolate spheroidal to oblate spheroidal.

      2. The highest percentage of pollen viability as tested by acetocarmine was in Lemon Oval and Sour Galgal, while the least in Amilbed (Gajanimma).

      3. The concentration of sucrose and glucose solutions as media for pollen germination varied with the variety.

      4. Pollen grains of Kaghzi lime in July bloom exhibited better viability and tube elongation than the pollen grains in March bloom.

      5. 5 ppm. of 2, 4-D in Sweet lime and 20 ppm. Boric acid, 20 ppm. 2, 4-D, 20 ppm. IBA, 5 ppm. IAA and 5 ppm. GA in Amilbed in combination with 20 per cent sucrose solution increased germinability.

      6. Pollen of Lemon Oval showed the maximum longevity of 20 days when stored at room temperature. Under low temperature conditions, the maximum longevity of 60 days was observed in Sour Orange and Karna Khatta.

    • Studies in the family Saxifragaceae - I. A contribution to the morphology and embryology ofSaxifraga diversifolia wall

      N P Saxena

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    • Embryological studies in Asclepiadaceae

      H Maheswari Devi

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    • On the multiseptate trichosclereids in the genus Scindapsus

      T Ananda Rao

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      The present study has revealed the presence of Trichosclereids in seven species ofScindapsus. They form distinct idioblasts in the lamina. A noteworthy structural aspect is the presence of septae in several sclereids.

    • The age of the Pakhals of the Godavari valley

      T Ramamohana Rao

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      The Pakhals consist of conglomerate, gritty sandstone, quartzite, slate, phyllite and limestone, and extend due north-west from the Singareni Collieries in the Godavari valley. The age of the Pakhals, whether they correspond to the Dharwars or the Cuddapahs or younger than the Cuddapahs has been a subject of controversy.

      Recent studies by the author on the structure and stratigraphy of the area around the Singareni Collieries have shown that the Pakhals lie unconformably on the granite gneisses as well as on a sequence of metasediments which consists of quartzite, phyllite, talc schists, chlorite schists, biotite schists, limestone, grünerite gneiss and ferruginous quartzite. The metasediments occur as two narrow strips, one in the neighbourhood of Singareni village and the other near Mulakalapalli, and are described as the ‘Singareni strip’ and the ‘Mulakalapalli strip’ respectively. The rocks of these strips were considered previously to be a part of the Pakhals but are now differentiated by the author as SINGARENI SERIES. Based on the available evidence, the ‘Shernavala strip’ of metasediments occurring to the east of Khammamett is considered to belong to the Singareni series, and the occurrence of baryte in this strip is shown to be genetically dissimilar to the occurrence of baryte in the Cuddapahs of the type area.

      The stratigraphic position of the Pakhals is clarified and it is shown that the granitic intrusion and/or granitisation involves the rocks of the Singareni series and not the rocks of the Pakhals. The position of the present area in the tectonic framework of the region is referred to and the structural disturbance at the south-eastern end of the Pakhal belt is related to the Eastern Ghats orogeny.

      The author considers the Pakhals to be Purana in age and presumably the time-equivalents of the Cuddapahs since they are overlain by the Sullavais. The Pakhals, lithologically dissimilar to the Cuddapahs and characterised by a general N.W.-S.E. strike, may probably be Late Dharwar in age.

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