Friday, 25 June 2021

Characteristic feature is the presence of chromodium inverted

   Characteristic feature is the presence of chromodium inverted

Comments Arcella is commonly found in stagnant fresh water containing much vegetation it is also found in moist forest soils moist sands and moss. It contains characteristic light yellow to dark brown shell or test which is made up of intricately arranged silicious, prisms set in a tectin base of reticular appearance. 

Ventral surface has an inverted, funnel like depression, leading to central mouth or cytostome. 1 to 6 small, hyaline, finger like, simple or branched lobopodia are extended through the pylome, which function as Locomotory and feeding organelles. Cytoplasm is differentiated into non vacuolated ectoplasm and endoplasm.

 Body is attached to the inner test wall by ectoplasmic stands or epipodia. Characteristic feature is the presence of chromodium or a peripheral layer of reticular cytoplasm. Endop
ontains various reserved food particles food vacuoles and contractile vacuole to prominent nuclei. Nutrition is holozoic. takes place by binary fission and partial extrusion of the body through pylome.

 Super Class II : Mastigophora (Flagellata) Simple, primitive animals Class Phytomastigoforea / Phytoflagellata Presence of chlorophyll (in chromatophore) Mainly autotrophic Locomotion by flagella. E.g. Ceratium. 

Called as disc which is slightly convex having vestibular opening ures 150 microns in length, excluding stalk, which 241 Zng nd of the body is typically tlattened bell or vase shaped on the side.Cytoplasm is differentiated in ecto and endoplasm. Periatome contains 2 rows of spirally coiled cilia, called as outer adoral cilia and inner adoral cilia forming ciliated dise.

Prepared-by squeez and bleaching or dyeing in sponge Euspongia

 Peristome leads into oral groove which is contained into vestibule. Vestibule has undulatory membrane. Ciliated dise rest on collar. Ectoplasm is devoid of trichocysts and contain pellicle and cotractile myonemes. Endoplasm is exclusively in body proper, and possesses food particles long and curved macronucleus and small micronucleus and cytopyge. Locomotion is rapid and by stalk and cilia. Nutrition is holozoic.

 Vorticella responds to external stimuli.  Phylum: Porifera The name Porifera (L. porus = pores, ferre Besring animals. Sponges belong to phylum Porifera. = to bear) means pore General characters Auticellular organisms with cellular grade of organization. uy marine, only one family Spongillidae is distributed in fresh water. All aquatic. Commonly called as sponges. Solitary or colonial, all sessile.

Rocky substratum Fig. Euspongia Euspongia is found in shallow water on rocky bottom. It sedentary form attached to the rocks by horny spone secretion. Commonly called as bath sponge attached to rocky substrate It attains a large and massive size with globular or cup-shaped body with dark black color. The slender spongin fibres fm småll network. Complex type of sponge, in which there is a further incres in the folding of the body wall.  

Bath sponge is of household use. It is prepared-by squeez and bleaching or dyeing in sponge. The common bath spe mainly consists of spongin fibres having the capacity of holdis water. 1.4 Phylum : Coelenterata Coelenterata are the first animals who have tissue gra of organization and division of labour. A central cavity or coelenter (Gr., koilos = hollow + enteron = gastro-vascular cavity. gut) functionally referred. 

Tuesday, 22 June 2021

The dorsal surface is convex and is covered with setae of different kinds

  The dorsal surface is convex and is covered with setae of different kinds

Aphrodite segms prostoniu palps palp stiff setae dorsal felt. neuropodia iridescent bristles soft setac stiff setae lar. Siridescent bristles ventral creeping sole gment. elytra ventral metameres anus neuropodial setae ad a d ves in Fig. Aphrodite : A. Dorsal View B. Ventral View Aphrodite is marine worm inhabiting the deep water muddy bottoms. Commonly called as sea mouse measuring approximately 12 cm in length and made up of 30 to 35 segments. e bas Body is covered dorsally by felt-like or blanket-like setae arising from the notopodium. 

Shape of the animal is oval, and dorsoventrally flattened. The dorsal surface is convex and is covered with setae of different kinds. Anterior end contains a small head or prostomium, bearing a small median tentacle and 2 lateral palps. Anus is dorsally situated at the more pointed posterior extremity. Parapodial structures are greatly modified. Notopodia contain 3 kinds of setae stiff setae (i) (ii) soft setae, and (iii) iridescent setae.Neuropodial setae are also brown and stiff. 

The soft notopodial setae are modified to form a felt-like covering over the back of the animal, while dorsal cirri become plate-like and are called as elytra, 15 pairs in number. The elytra obtain dissolved oxygen from the sea water circulating around them. Ventral surface is flat, segmented and forming a creeping sole. Each ventral segment or metamere contains stiff setae. Pumping action of the dorsal body wall causes the sea water to be filtered through the dorsal felt into the space below.

 Animal rolls itself with erect stiff setae like porcupine to protect itself from enemies when disturbed. During movement of the animal, color changes from gold to peacock. Class II: Oligochaeta (Gr., oligos = few + chaite = Few setae in each segment. Clitellum present. E.g.

 Earthworm = hair) Example : Earthworm (Pheretima) mouth prostomium.Organ system level of body organization. Jointed legs (appendages) Exoskeleton of dead chitinous cuticle. Body divided into head, thorax and abdomen. Head and thorax often fused to form a cephalothorax. Coelom replaced by haemocoel. 

 Composed of cellular plates consisting of two upper epithelical

Phylum protozoas is divided into two sub-phyla on the basis of organs Phylum : Protozoa Sub phylum Ciliophora sareomastigophora Class Class Ciliata Sarcodina Mastigophora Opalinata Sub phylum A: Sarcomastigophora Locomotory organs are pseudopodia, flagella or none. Cilia absent. Nuclei of one kind. Super Class I: Sarcodina (Rhizopoda) Locomotion by pseudopodia. Nutrition holozoic or saprozoic. Class Rhizopodea Pseudopodia may be lobopodia, filopodia or reticulopodia. Example: Arcella lobopodia ectoplasmie strands nuclei ectoplasm endoplasm pylome food vacuole Fig. Arcella. 

Ceratium apical pore theca nucleus ectoplasım- endoplasm apical spine annulus chromoplast- starch granules pore for posterior passage of ? agellum lateral spine upper epithecal plates annulus II transverse spiral sulcus lower posterior flagellum hypothecal plate A Fig. Ceratium Ceratium is found in fresh water as well as in sea.They are important members of 'ocean meadows' on which other animal feed. Body is green or brown colored. 

Body is composed of cellular plates consisting of two upper epithelical plates and two lower hypothetical plate. Epithelical plates are produced anteriorly as apical spine. Two posterior hypothecal plates are produced on each side as lateral spines. Shell is grooved by transverse groove and a longitudinal groove or sulcus. 

Transverse groove is called as annulus. Each transverse groove nas spiral transverse flagella and longitudinal groove has posterior flagella, each flagellum projects in cytoplasm. : Cycas - L.S. of seed The nucellus is used up. 

Thursday, 17 June 2021

Indistinct inter-radial oral madreporite Ophiocoma is commonly

   Indistinct inter-radial oral madreporite Ophiocoma is commonly

Month is very widely distensible, which can swallow bivalves. molluscs, snails and crustaceans very easily. Aboral surface has madreporite in one of the interradii. Skin is soft and somewhat transparent and internal skeleton is seen from outside. Aboral surface contains blunt spines, finger-like dermal branchiae and pedicellariae, In some forms spines are absent. Sexes are separate. The development includes brachiolaria larva. Class II:Ophiuroidea (Gr., ophis = snake + oura = tail + eidos = form) Commonly called as brittle stars. Central disc and arms are sharply demarcated. E.g. Brittle star Example : Brittle Star upper plates central disc spines arms Fig. Brittle star. 

Ophiocoma is commonly found in shallow waters.. Commonly called as brittle star. Body consists of a small, rounded central disc and 5 long slender, kapering arms, which are inserted on the under-surfaces of the disc. Central disk and arms quite distinct. Arms are distinctly marked off from the central disc and do not have prolongations of perivisceral coelom and alimentation. Oral and aboral surfaces are distinctly marked. Oral surface has leathery skin. Anus and pedicellariae absent. Oral surface has a central, pentagonal mouth opening and indistinct inter-radial oral madreporite. The ambulacral covered. grooves There are 10 elongated slits, two on either side of the base of each arm, called as genital bursae m which gonoducts open. 

Three rows of pointed spines are borne on lateral plates. Single row of short tube feet projects on each side between lower and lateral plates. Ossicles of arms are articulating. Class : Echinoidea (Gr., echinos hedgehog + eidos = form) %3D %3D Commonly called as sea urchins and sand dollars. Body disc shaped, egg shaped or heart shaped. E.g. Sea urchin Example : Sea Urchin ambulacra peristome oral tentacles radial or ocular anus genital plate plate teeth periproct- madreporite tube feet spine branchiae tubercles podial poros ambulacral sone or ambulacrum spines interambuacral zone or interambulacrum interambulacra. 

Crinoidea (Gr., crinon = lily + eidos = form) 65 %3D %3D Commonly called as sea lilies. . Body consists of a cup like calyx and cylindrical arms. Tube feet, madraporite and pedicellaria absent. E.g. Feather star Example : Feather star pinnules arms oral surface of central dise calyx mouth anus embulacral aboral cirri grooves Antedon is marine and occurs about 2 fathoms deep and remains attached to rocks by cirri from central disc. Commonly called on sea-lily or feather-star. 

On the aboral side calyx bears a knob-like structure called as Centro-dorsal plate or stalk. The calyx is differentiated into an upper convex oral surface, having mouth and anus and the lower flat aboral surface into which arms and cirri are inserted. On the aboral side calyx bears a knob-like structure, called as stung of the stalk. The oral surface is covered by a leathery skin in which numerous calcareous plates are embedded It is directed upwards.

Common gonopores of successive Proglottids lie alternately

 Testes : Testes are numerous small, spherical bodies scattered throughout the mesenchyme, close to the dorsal surface. It consists following organs. (b) Vasa efferentia : From each testis arises a fine ductule, the vas efferens, which frequently gets interconnected with similar ductules from the surrounding testes. All the vasa efferentia finally unite, approximately in the middle of proglottid, to form a common sperm duct or vas deferens. 

(c) Vas deferens : It is a thick and convoluted tube, extending upto the lateral margin of proglottid, at right angles to it. (d) Cirrus : Outer end of vas deferens forms the lumen of a thick, muscular, eversible, copulatory organ, the cirrus. There is no seminal vesicle. (e) Genital atrium : Cirrus opens into a cup-shaped genital atrium through the male genital pore., Genital atrium, in turn, opens to the exterior through the common gonopore situated at the peak of a tiny protuberance, the genital papilla, in the middle of the lateral margin of Proglottid. Gonopore is provided with a sphincter muscle. 

Common gonopores of successive Proglottids lie alternately on both the sides. Female Reproductive system It consists following organs. (a) Ovary : A single bilobed ovary or germarium lies ventrally in thd posterior part of proglottid. Each lobe of the ovary is dorso- ventrally flattened and consists of a number of radially- arranged germinal cords or follicles.  (b) Oviduct : A short oviduct arises from about the middle of ovarian isthmus. It runs backwards, joins another slender tube, the vagina and then forms a swollen chamber, the ootype.

and nervous systems; and they are formed at the zone of prolife by muscles, excretory vessels and nerve cords. Proglottic independent, self-contained units, each with a complete strobila. The strobila forms the main bulk of the body and co reproductive organs both male and female and a. proglottisation. The proglottids, internally, remain connected to of a series of proglottids arranged in a linear fashion. The st of a mature tapeworm measures about three metres in length 800 to 900 proglottids.

 A proglottid is one complete unit of the linear arrangement of repetition of these units is having a complete set of genitalium and surrounding tissue The neck is followed by the flattened, ribbon-like body small hook FORMS AND FUNCTIONS IN ANIMALS hand rostellum two rows of hooks Scolex biade C handle Suckers neck showing strobilation A large hook blade bas Tape worm : A Scolex and neck; B Scolex in en-face view: C Small hook; D Large hook [2] Neck Behind the Scolex is a thin, small, narrow, unsegmented neck grows continuously and proliferates proglottids by transversef or asexual budding. Therefore this region is variously calle growth zone, area of proliferation, or budding zone etc. [3] Strobila part of ex differentiated into three kinds.