Volume 33, Issue 1
January 1951, pages 1-48
pp 1-13 January 1951
The paper narrates the results of an experimental enquiry on respiration rate of sugarcane leaves of different stages of development under four conditions of nutrition,viz., complete nutrition, nitrogen deficiency, phosphorus deficiency and potassium deficiency. The experiments were conducted at maturity stage on five varieties of sugarcane,e.g., Co 453, Co 421, POJ 2878, Co 205 and Rheora grown in sand in pots.
Co 205 and Rheora show high leaf respiration as compared with Co 453 and POJ 2878, having significantly lower respiration rates. No differences in leaf respiration upto the third or fourth leaf stage are noted; beyond this the greater the stage of leaf development, the lower is the respiration of leaves.
Nutritional conditions bring about considerable changes in respiration of leaves. Thus nitrogen deficiency shows normal leaf respiration at maturity as compared with either phosphorus or potassium deficiency, each of which exhibit supernormality in respiration.
Variations in respiration rate under these conditions appear to be determined by changes in chemical composition of leaves, particularly nitrogen and carbohydrate fractions. Observed differences in respiration are discussed in the light of such changes.
pp 14-31 January 1951
The occurrence ofPisione remota (Southern) in the tropical environment at Madras is recorded and the external characters of specimens from Madras compared with those from Irish waters.
The reproductive structures in the two sexes have been described in detail.
While distinct specific features are found in the detailed structure of the accessory reproductive processes, a strong resemblance to the condition inP. gopalai andP. complexa is observed.
The salient features of the four valid species of the genusPisione have been tabulated and based on this the generic characters have been revised.
The affinities of the family Pisionidæ have been considered in the light of our knowledge of the anatomy ofPisionidens indica, Pisione gopalai,P. complexa andP. remota, and probable relationship to the Phyllodocidæ, the Glyceridæ and the Nephthydidæ has been indicated.
A revised statement of the characters of the family Pisionidæ has been given, incorporating in it our knowledge of the internal morphology of the species included in the same.
pp 32-40 January 1951
pp 41-48 January 1951
In the Eocene of Pakistan, India and Burma, two genera—Miscellanea and Pellatispira—have shown a remarkably stable and limited vertical range in the several areas in which representatives of these genera are found. Miscellanea, which is represented byM. miscella (d’Archiac and Haime),M. stampi (Davies), andM. meandrina (Carter), is confined to the Ranikot (Palæocene age) in all the areas examined so far, while Pellatispira, which is represented byP. cf. orbitoidea (Provale),P. cf. inflata Umbgrove,P. cf. madaraszi Von Hantken,P. cf. glabra Umbgrove, is found only in the very high Eocene (Upper Eocene) beds. Because of their very restricted vertical range these two genera are of considerable stratigraphic value.