Volume 69, Issue 5
May 1969, pages 235-294
pp 235-240 May 1969
1. Carbonic anhydrase in the gills of the freshwater teleost,Etroplus maculatus, was demonstrated to be influenced by transfer of the animal to saline media.
2. Sudden and direct exposure of the fish to saline media resulted in a decrease of the enzyme activity.
3. The enzyme activity was reduced gradually with progressive increase of the salinity after two months acclimation of the fish in the medium.
4. It was concluded that reduced carbonic anhydrase activity of the gill on acclimation to higher salinities, is associated with Cl− uptake but not Cl− excretion.
pp 241-251 May 1969
The present study deals with the shoot apical organisation, leaf and axillary bud initiation and their development inCapparis decidua. The shoot apex exhibits four cyto-histological zones during most of its plastochronic cycle. The number of tunica layers varies from 2–3 in different phases of plastochron. An additional zone of ‘cambium-like’ cells was observed during the mid-plastochron phase. This zone is ephemeral. In leaf initiation the inner layers of tunica and the flanks of the corpus take part. The procambium differentiation in leaf is acropetal. Axillary bud initiates from ‘detached meristem’. The ‘shell zone’ separates the axillary bud meristem from the shoot apex. The shell zone is seen during early stages of axillary bud formation and it disappears soon. The flanks of the corpus mainly take part in the initiation of axillary bud, the tunica layers continue as discrete surface layers of axillary bud. The procambium differentiates acropetally in axillary bud.
pp 252-255 May 1969
pp 256-258 May 1969
Sonerila sadasivanii Nayar, a new species from South India, is described with illustrations.
Sonerila sadasivanii Nayar, sp. nov.S. bruncni W. and A. peraffinis, sed caulibus quadrangularibus alatisque, margine foliorum subtiliter serrulato atque cartilagineo, petiolis crassibus differt.
pp 259-268 May 1969
Studies on the cephalochordates of Madras coast - V. The effect of the concentration of particulate matter and the oxygen tension in sea-water on the filtration rates of AmphioxusBranchiostoma lanceolatum
1. Previous work on the methods of measurement of the filtration rates in different animals is discussed and the advantages of direct determinations emphasised.
2. Methods of the technique and the details of the apparatus for determining the filtration rates are given.
3. The normal rates of filtration in habitat sea-water,i.e., with the normal concentration of particulate food and oxygen content were determined for different sizes of lancelets.
4. The rates of filtration in 100% (normal habitat sea-water) 150%, 200%, 50% and 0% concentrations were determined.
5. The rates of filtration in media of different oxygen content (3·60, 2·91, 1·79 and 0·56 ml./l.) were determined. It was found that the filtration rate slackens as the oxygen content is reduced upto 1·79 ml./l. and increases in a still lower content of 0·56 ml./l.
6. The influence of the concentrations of particulate food and of oxygen content on the filtration rates are discussed and the greater importance of particulate food is stressed.
pp 269-276 May 1969
The paper deals with the description of two new nematode species of the genusAbbreviata as well as a redescription of another hitherto inadequately described speciesA. achari (Mirza, 1935).
pp 277-283 May 1969
The morphology, anatomy and stages in life-history ofCercaria andhraensis n.sp. from the apple snailPila globosa Swainson of Waltair have been described.C. andhraensis has 33 spines which are inconspicuous in the cercaria but are clearly seen in the metacercaria occurring in the snail host itself. The anatomy of the cercarial tail is given in detail. Differences in the tegument of the body and the tail are indicated. The tail tegument more clearly gives the impression that the so-called tegument of trematodes is a modified epidermis. It is suggested that the cercaria and the metacercaria may one day prove to be the stages of eitherEchinostoma govindum Moghe, 1932, orE. crecci Verma, 1936.
pp 284-293 May 1969
pp 294-294 May 1969 Erratum