The process of regeneration is somewhat intricate and involves multiple organization highlighting replacement of the lost parts  through reawakening of morphogenesis at the late phase of ontogeny. The characteristics of this process may be epimorphic or morphollactic has been stated by several developmental biologists. Indeed the exact definition of the regeneration is difficult to ascribe and several investigators have attempted to define the phenomenon on the basis of their observations be it on recapitulation of development processes (progressively restricted by age) reconstitution of the lost parts physiological parameters cellular and sub cellular level or phyllogenetic status  of the organism concerned and so on. In short it may be stated as anatomical growth established on the later stages of ontogenesis to re establish the physiological process in the long run.

The present investigation embodies the following perspectives:

Cephalic regenerative potentials in M.peguana .

• Week wise growth and development of the regeneration blastema.
• Sequential development of the nerve ring .
• Correlated cytomorphic changes in the ganglionic neurosecretory elements.
• Relationship of the neurosecretory elements and their moniliform axon terminals and fibers with extra and intraganglionic vascularization and the exposition of the neurosecretory granules at the accumulation sites--- A Lightmicroscopic observations

The primary productivity of any aquatic ecosystem depends on the plank tonic bio diversity. Plankton is starting point of energy transfer in the aquatic ecosystem and their well –being is of paramount importance to the over all health and integrity of the system. Qualitative and quantitative analysis of different groups of organism lead to the establishment of bio – indicator, indices and systems which can be assess the pollution and tropic status of water bodies. The present study was aimed to find out the impact of higher population on the plankton population of the Gandak river. Plankton samples were collected from Hajipur [New pool ghat 100 mit far away] sites during the study period [Oct. 2016 – Sep. 2017] for three seasonal variation winter, summer and rainy season. Plank tonic diversity in presence of phytoplankton is higher 248 ±19.82 in winter season and lower 11.64 ± 14.26 in rainy season and Zooplankton is higher 51.78 [Rotifera] in winter season and lower is 18.29 [crustacean]in rainy season. Studies revealed that phyto plankton population was dominated by members of Chlorophyceae, Bacillariophyceae, and Cynophyceae and Zooplankton population was dominated by Rotifer, Crustacea and Protozoan. The present study was to assess the status of phytoplankton diversity and biomass in order to know the productivity of Gandak River. A total 29 species, 13 chlorophyceae, 7 Bacillariophycea  and 9 Cyanophyceae and in Zooplankton  total  5 species of Rotifera, 4 species of Crustacea and 7 species of Protozoa is maximum to minimum were observed.

The present study was undertaken to assess the water quality by the analysis of its physico chemical parameters. This study was taken on Thimmapur freshwater Lake of Warangal district, Telangana, India. The water quality parameters studied in the present investigation were Water temperature,  pH, Turbidity,  Dissolved oxygen, Biological Oxygen Demand, Alkalinity, Chlorides, Total Dissolved Solids and Hardness. Monthly changes in physico-chemical parameters were analysed for a period of one year from February, 2016 to January, 2017.  Based on the results of present study, it was found that some physico- chemical parameters showed seasonal fluctuations. The results obtained in this study also indicats that the quality of water of this lake is within the permissible limits. However continuous monitoring of the water quality is very important in order to maintain the water quality of this lake and it reveals that the pollution status of this is not much inspite of some anthropogenic activities like washing of clothes and cattle in the Lake. Finally it can be suggested that this lake water can be used for Irrigation and Pisciculture

A histopathological study of the gill of the fish Ctenopharyngodon idella is reported after exposure to sublethal concentration of Deltamethrin (1/10^th of 96 h LC₅₀ value 0.0172 of continuous flow through system), 11% EC, a synthetic pyrethroid, for 10 days.  The gills, both primary and secondary  filaments observed  bulging and distortions   Apart from this some  other alterations such as degenerative changes in the intralamellar cells and spaces, separation of epithelial layer from the central sinus of filaments and severe proliferation of epithelial cells and club shaped secondary lamellae as progressive degeneration of the gills are other pathological changes also noticed.

The Heavy metals are most vulnerable environmental pollutants and their toxicity has been increasing significantly in the environment. The present study evaluates the occurrence and content of heavy metals such as Lead (Pb), Chromium (Cr), Cadmium (Cd), Iron (Fe), Zinc (Zn), and Copper (Cu) in the water samples of Chinnawaddepally lake of Warangal District, Telangana State.There are four sampling sites were identified on the basis of the entry of pollutants in the lake. The heavy metal content concentrations have shown higher to lower in the  following order i.e Fe > Cu > Pb > Zn > Cd > Cr. The area under study receives domestic sewage and especially it is the site for idol immersion which take place in a large scale during and after several regular intervals.

The present study of the seasonal abundance of some plankton in the river Ganga with particular reference to water pollution is observed seasonally during November 2016 to September 2017 from three stations of Doriganj, Chapra, Bihar. According to the present study, 3 groups of phytoplankton and 4 groups of zooplankton were observed, their percentage in different seasons were, Chlorophyceae ( summer– 31.82%, winter- 45.45%, monsoon- 22.73% ), Bacillariophyceae ( S- 30.86%, W- 43.21%, M- 25.93% ), Myxophyceae ( S- 30%, W- 46.66%, M- 23.33% ), Rotifers ( S- 17.14%, W- 74.29%, M- 8.57% ), Copepod ( S- 18.6%, W- 74.42%, M- 6.98% ), Cladocera ( W- 88.06%, M- 11.94% ) and Ostracopoda     ( S- 40.43%, W- 55.32% and M- 4.26%). The phytoplankton and zooplankton were observed maximum in winter season and minimum in monsoon season. During the present study, relevant correlation showed total phytoplankton had a highly significant relationship with TDS (-0.83), DO (0.92), and temperature (-0.93). Zooplankton had also highly significant relationship with TDS (-0.93), DO (0.98) and temperature (-0.98).