• Volume 17, Issue 5

      May 1943,   pages  133-155

    • Trematodes from Indian Marine Fishes - Part III. description of a new species of the genusmehratrema (familymonodhelminthidae Dollfus, 1937)

      B S Chauhan

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    • Volume relations of the nucleus in apodan spermateleosis

      B R Seshachar

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      Seeing that this is the first attempt at a determination of the changes in the volume of the nucleus during spermateleosis, it would be hazardous to draw any far-reaching conclusions on the data available. But one striking fact that emerges from a study of the above figures is the enormous reduction in the volume of the nucleus from the spermatid to the fully formed sperm. This reduction is approximately 95% inSiphonops annulatus, 90% inIchthyophis glutinosus, Urœotyphlus narayani andGegenophis carnosus and 80% inDermophis gregorii. It is therefore clear that the chromatin of the nucleus accounts only for a small quantity of its volume.

      Another fact that strikes one from an examination of the Graph (Fig. 1) and Table I is that so far as the five species of Apoda are concerned, in spite of the large variation in the nuclear volumes of the different species in stages I and II, the volume in the third stage,i.e., in the fully formed sperm, is nearly the same in all the species. What significance is to be attached to this fact will not be clear till more species are examined, but the close similarity in nuclear volume of the adult sperms of these five different species of Apoda is interesting.

    • Surface and interior effects in unstriated muscle produced by various ions

      Inderjit Singh

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      Ions such as potassium, ammonium, hydrogen, to which the mu scleis permeable, neutralise the contractures produced by ions to which the muscle is comparatively less permeable, such as sodium chloride, adrenaline, acetylcholine. This suggests that excitation is caused by difference in concentrations of ions within and without the cells.

    • Reversal effects in unstriated muscle

      Inderjit Singh

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      1. Hydrogen ions may convert an excitatory effect into an inhibitory one.

      2. Calcium, sodium chloride and caffeine may produce reversal effects.

      3. Presence of tone alters an excitatory effect into an inhibitory one.

      4. Anions may convert an inhibitory effect into an excitatory one, and cations may produce an opposite effect.

      5. Reversal effects are also produced by adaptation, fatigue, inexci-tability and change of length.

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