• P N Ganapati

      Articles written in Proceedings – Section B

    • On a newMyxosporidian henneguya otolithi n. sp. a tissue parasite from the bulbus arteriosus of two species of fish of the genusOtolithus

      P N Ganapati

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      A new species of a polysporous tissue infecting myxosporidian,Henneguya otolithi is described from the bulbus arteriosus of two species of a marine fish,Otolithus ruber andO. maculatus.

      Two kinds of nuclei, the vegetative and generative, are present in the earlier stages of the parasite. The vegetative nuclei are not present in later stages.

      The pansporoblasts originate by the copulation of anisogamous gametes.

      Evidences of multiplicative reproduction by plasmotomy in young vegetative forms are seen.

      Autogamy is present and instances of auto-infection have been observed.

      The histopathological processes in the infected organ are described.

      Diffuse infiltration of spores is common and scattered spores have been located in the kidney.

      A seasonal variation in the occurrence of the different stages of the parasite is noted. In general a higher temperature seems to accelerate spore formation.

    • The development and sporogony of a CoccidianMyriospora Gopalai n.sp., parasitic in the gut of the polychÆteCirratulus filiformis Keferstein

      P N Ganapati

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      The development and sporogony of a new Coccidian,Myriospora gopalai n.sp., are described, from the gut of a polychæteCirratulus filiformis.

      Merozoites are large and elongated with characteristic siderophil bodies at one end.

      Microgametocyte is long and cylindrical producing 60–80 microgametoblasts. Each microgametoblast develops independently, forming 6–8 crescent-shaped biflagellate male gametes.

      The females are shorter and broader than the males.

      The chromosome number during microgametogenesis and in the nuclear division of the oocyst is haploid and it is believed that the diploid number is restored at the time of fertilisation. The first zygotic division is probably a reduction division.

      Oocysts are ovoidal with a characteristic thickening of the wall at one end. 8–16 Sporocysts are formed by each oocyst. Sporocysts are polyzoic containing 24–32 sporozoites.

      Schizogony was not observed and this question is discussed.

      The systematic position of the genusMyriospora Lermantoff is discussed and it is pointed out that the criterion of the oocyst structure alone cannot be emphasised in separating the polysporocystid Eimeriid genera.

    • On lecudina pellucida (kÖlliker) mingazzini (1891) from the gut of nereis chilkaensis southern

      P N Ganapati

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      The detailed morphology and life-history of a dicystid gregarine,Lecudina pellucida (Köll.) Mingazzini, from the gut ofNereis chilkænsis Southern, are described.

      The young stages of the parasite are intra-epithelial while the adult trophozoites lie free in the lumen of the gut attached to the intestinal wall by a sucker-like epimerite.

      Cyst-formation takes place in the mid-gut and further development of the cysts takes place outside the host.

      Gametogenesis is completed in about 48 hours. The gametes are anisogamous.

      Spore-formation takes place in about 3 days and the spores are scattered by simple rupture of the cyst. The sporocysts are ovoidal with a thickening at one pole. There are eight sickle-shaped sporozoites and a spherical sporocyst residuum.

      The systematic position of the genusLecudina Mingazzini and of the family Lecudinidæ Kamm are discussed in the light of these observations.

    • Notes on some gregarines from polychÆtes of the Madras Coast

      P N Ganapati

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      Four genera belonging to seven species of Eugregarines and two genera comprising of five species of Schizogregarines are described from some common polychætes found at Madras. The hosts examined include nine genera of as many species.

      Of the seven Eugregarines described six are new to science, and all of them come under the family Lecudinidæ Kamm emend Reichenow, 1929. The three genera,Polyrhabdina, Sycia andAncora are recorded for the first time from India. The retention of the genusSycia Leger as different fromUlivina Mingazzini, and its inclusion in the family Lecudinidæ have been suggested.

      The Schizogregarines described come under the generaSelenidium Giard andSiedleckia Caull. and Mesn. Four new species ofSelenidium are described while the fifth one has been provisionally assigned to this genus. The genusSiedleckia is a new record from India.

    • On the vertical distribution of chemical constituents in the shelf waters off Waltair

      P N Ganapati E C La Fond P V Bhavanarayana

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      The chemical composition of the shelf water has been investigated and examples of the vertical chemical structure are given in the table. From these values and other related hydrographic information the chemical factors controlling the composition of the shelf water may be discussed.

      The range of salinity between surface and bottom was greater during the period of sinking and lower during upwelling. The high values of salinity, phosphate, silicates and oxygen were influenced by upwelling. The advection of Northern Dilute water and Southern Bay of Bengal water also affect the vertical and horizontal chemical structure of the water. These were further modified by planktonic consumption during periods of accelerated production. A detailed report is under preparation.

    • Quantitative study of plankton off Lawson’s Bay, Waltair

      P N Ganapati D V Subba Rao

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      Observations on the hydrographical and planktological conditions of the surface waters at a fixed station located at the 10 fathom line in the Lawson’s Bay, Waltair, have been made for the year 1956.

      The influence of the prevailing currents on the hydrographical conditions in the inshore waters of the Bay of Bengal is discussed. A north to south succession of the periods of low salinity and high silicate content at three stations Waltair, Madras and Mandapam on the east coast of India has been observed during the southerly current period, July to December. A similar succession of the high salinity values in a south to north direction during the northerly current period, January to June, has also been observed at Madras and Waltair.

      Quantitative plankton estimations have been made by counting, volume estimation, pigment extraction, total biomass and total organic matter for known volumes of water. There was general agreement between the data using the different methods.

      A major phytoplankton peak during March to April and a minor phytoplankton peak during October to November were observed. The diatom and dinoflagellate maxima coincided with each other.

      Pigment extraction was made with three different solvents and it was found that ethyl alcohol-benzene mixture was a better solvent than acetone and methyl alcohol.

      A general discussion is given on our observed data of plankton production in relation to the hydrographical conditions and inferences drawn in the light of similar investigations from Indian waters and elsewhere.

    • A new haplosporidian parasite,Coelosporidium schmackeriae from the body cavity of a marine copepodSchmackeria serricaudata

      P N Ganapati C C Narasimhamurti K Shanthakumari

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      1. The morphology and life-history of a new haplosporidian parasite,Coelosporidium schmackeriae, from the body cavity of the copepodSchmackeria serricaudata is described.

      2. The earliest stage observed was an amoebula which developed into multinucleate plasmodia.

      3. The plasmodia may undergo a process of asexual multiplication or plasmotomy and this may be repeated.

      4. Spore formation took pláce inside the plasmodia by the fragmentation of the cytoplasm into uninucleate bodies and these bodies ultimately developed into uninucelate simple spores enclosed in a common cyst.

      5. Cysts are ovoid measuring 25·0µ in diameter and enclose 70–80 spores. The spore is ovoid measuring 3·0µ × 27sd5µ and provided with a rigid double envelope. Neither an operculum nor a bivalve nature of the spore was noticed.

      6. The systematic position of the parasite is discussed.

    • On a new species ofSphaerosyllis (Polychaeta) from the beach sands of Waltair coast

      G Chandrasekhara Rao P N Ganapati

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    • On some interstitial polychaetes from the beach sands of Waltair Coast

      G Chandrasekhara Rao P N Ganapati

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      The paper reports the occurrence of eight species of microscopic interstitial polychaetes in the sandy beach of Waltair Coast. All the eight forms have not previously been recorded from India. Among the forms reported some are previously known only from the Atlantic and their occurrence in Indian Ocean throws considerable light on their geographical distribution.

    • On some marine interstitial gastrotrichs from the beach sands of Waltair Coast

      P N Ganapati G Chandrasekhara Rao

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      The paper reports for the first time the occurrence of thirteen species of interstitial Gastrotrichs in the beach sands of the Waltair Coast which were previously reported from European waters. Eight of the species representing seven genera belong to the order Macrodasyoidea and the remaining five representing three genera come under the Chaetonotidea. The distribution of these forms is described with reference to the tidal levels, the grain size of the sand, the temperature and salinity ranges of the environment.

    • On some archiannelids from the beach sands of Waltair Coast

      G Chandrasekhara Rao P N Ganapati

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      The paper reports the occurrence of twelve species of Archiannelids in the interstitial sands of the Waltair beach. Of these, six European species are reported for the first time from Indian waters and their occurrence on the Indian coast is of great interest from a Zoogeographical aspect of their distribution.

    • Some new interstitial gastrotrichs from the beach sands of waltair coast

      G Chandrasekhara Rao P N Ganapati

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      The paper reports for the first time the occurrence of eleven new species of Gastrotrichs in the interstitial sands of Waltair beach. Ten of these belong to the order Macrodasyoidea and the other to the order Chaetonotoidea. The distribution of these forms in relation to the size of the sand grains and depth has been described. The feeding habits and the other interstitial fauna associated with the Gastrotrichs have also been reported.

    • Some new interstitial copepods from Waltair coast

      G Chandrasekhara Rao P N Ganapati

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      The paper reports the occurrence of eight new species of harpacticoid copepods from the interstitial sands of Waltair coast. These belong to 7 genera. The description and distribution of these forms with reference to the size of the sand grains, depth and tidal levels are given in the paper.

    • Some observations on the structure and life-history ofCercaria andhraensis N.Sp. (Trematoda: Echinostomatidae) from the apple snailPila globosa Swainson of Waltair

      P N Ganapati K Hanumantha Rao

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      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.

    • On some interstitial copepods from the beach sands of waltair coast

      G Chandrasekhara Rao P N Ganapati

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      The present paper reports the occurrence of twenty species of marine interstitital Copepoda from the beach sands of Waltair coast. Half of these are recorded for the first time from Indian waters. The males of some of the species are described for the first time. A new subspecies has also been created.

    • Distribution of pelagic tunicates in the western part of the Bay of Bengal

      P V Bhavanarayana P N Ganapati

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      A total of thirty-three species and two varieties of pelagic tunicates are reported from the western part of the Bay of Bengal. The influence of the prevailing water movements, temperature and salinity on the distribution of pelagic tunicates at the surface and in the subsurface is considered. The suitability ofOikopleura intermedia, Fritillaria borealis f. sargassi, Fritillaria pellucida, Thalia democratica var.orientalis and the western-Pacific form ofThalia democratica as indicators of water movements is suggested.

    • Ecological aspects of zooplankton production off Visakhapatnam (bay of Bengal)

      K V Ramanamurty P N Ganapati

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      The quantitative distribution of zooplankton off Visakhapatnam was investigated during the period March 1968 to February 1970. The seasonal data on the parameters like surface water temperature, salinity and oxygen were recorded. The seasonal abundance of zooplankton was estimated by volume, dry weight and numerical estimation. In general, a similarity was observed in the trend of the numbers, volume and dry weight values. Peak periods of zooplankton occurred during March–April, July–August, and November–December. In general, the major and minor peaks of abundance coincided with the south-west monsoon and north-east monsoon respectively. The major fluctuations in the numbers of total zooplankters were largely due to fluctuations in the numbers of copepods. Considering the higher turnover rate consequent on higher rate of metabolism and the occurrence of several broods in a year the standing crop of zooplankton in tropical waters may be actually more than in temperate waters. The factors which may be responsible for the variation in the quantitative abundance of the zooplankton, during the two monsoon currents, in the present area are discussed.

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