Shashank Mishra gonda

-:Body cavity or Coelom:- The body of Nereis is transverse section looks like a tube within a tube . The wall of the outer large tube is body wall and the wall of the inner small tube is the gut wall . In between the two walls,lies a spacious cavity called coelom or body cavity , which is filled up with afluid . The coelom is thus lined externally by parietal epithelium and internally by visceral or splanchnic epithelium . The coelom is devided into compartments by transverse partitions,called septa . The wall of each septum is perforated through which coelomic fluid communicates from one chamber to the other. Coelom of Nereis is schizocoelic and filled with coelomic fluid having amoeboid corpuscles . It act as hydrostatic skeleton and help in transportation of digested food,gasses and waste materials . -:Locomotion:- In Nereis Locomotion takes place by parapodia, musculature and coelomic fluid . Nereis shows three types of locomotion - Slow creeping :- This ty...

-:Body wall of Nereis:- The body wall is divisible into - (a) Cuticle.               (b) Epidermis. (c) Muscles layers. (d) epidermis.  (a)Cuticle:- It is thin, slightly brittle and chitinous,non cellular. A number of minute openings are present on the cuticle through which the epidermal gland open to the exterior. (b) Epidermis:- This is formed by a single layer of cells. It is more thick on the ventral side specially near the parapod i al joints. The dorsal side of the epidermis is richly supplied with blood vessels. Numbers of 'twisted' unicellular glands are present specially on the ventral side. (c) Muscle layers:- The outer muscular layer is circularly arranged and the inner layer runs longitudinally. The longitudinal muscles are present in four bundles - two  are dorso-lateral the remaining two are ventro-lateral . The circular muscle of dorsal and ventral sides are interconnected ...

कर्फ्यू और लॉकडाउन जब खुलेगा तब मेरे जैसे कुछ निकम्मे यही भूल जाएंगे कि वे काम क्या करते थे 😂🤣😂🤣😂🤣

-:Parapodium:- All the segments excepting the first and the last segments bear on either lateral side a fleshy,flat and hollow parapodium . Largest parapodia are encountered in the middle segments of the body,then the size of the Parapodia decreases towards the two ends. Each parapodium is biramous in nature. It consists of a basal part and two distal parts- >Dorsally placed notopodium*. >Ventrally placed neuropodium*. Both these parts are sub-divided into lobes and both of them carry pack of needle-like structures, called setae which project beyond the lobes.  Cirrus (Pl.cirri):-               The dorsal and ventral sides of the parapodium bear small, tentacle-like, cylindrical appendages, called dorsal and ventral cirrus respectively. The ventral cirrus situated ventral to the neuropodium,is smaller than the dorsal cirrus situated dorsally on the notopodium. Setae:-    ...

-:Nereis:- Or -:Neanthes:- (Clam warm ) Systematic position :- Phylum-.  Annelida Class-       Polychaeeta Order-.           Errantia Family-.         Nereidae Genus-.     Nereis Species-.         Virens Distribution :-               Nereis is cosmopolitan* in distribution. It is found abundantly in Europ, North America etc. -:External Structures:- i.Shape:-         Body is elongated, slender Bilaterally symmetrical and slightly flattened* ii.Size:-             Length is varries from few to 40 cm or more. iii.Colour:-              The colouration is varies from species to species...

प्रकृति का नियम :-  जब आप सु धर जाते हैं तभी आप के कांड बाहर आते हैं 🤣🤣😂😅