Kingdom Animalia

Coelom is secondary body cavity exists between the body wall and the digestive tube and is lined on all sides by mesoderm.

Wuchereria bancrofti (the filarial worm) belongs to phylum-Nemathelminthes. It is digenetic-the primary host is human and intermediate host is mosquito (certain species of Culex and Aedes). The accumulation of these worms blocks the lymphatic system resulting inflammation of lymph gland and other pathological conditions. In some cases, the obstruction of lymph vessels may cause a serious disease known as elephantiasis (filariasis) in the legs and arms.

The true coelom is a body cavity which arises as a cavity in embryonic mesoderm. In this case, the mesoderm of the embryo provides a cellular lining, called coelomic epithelium or peritoneum, to the cavity. The coelom is filled with coelomic fluid secreted by the peritoneum. The animals which have true coelom are called eucoelomates or coelomates, eg, annelids, echinoderms and chordates. Among given option Pheretima (annelid) has tme coelom (shizocoel). The coelom is filled with milky white alkaline coelomic fluid.

In arthropods, the body is covered with a thick, tough and non-living cnitinous cuticle, which forms the exoskeleton. The latter is moulted entire at intervals, eg, cockroach.

Psittacula (parrot) is not a flightless bird, while other three are flightless birds.

Earthworm is not a deuterostome. Deuterostomes are distinguished by their embryonic development. In these animals, the first opening (the blastospore) becomes the anus, while in protostomes it becomes the mouth. Deuterostomes are also known as enterocoelomates because their coelom develops through enterocoely. There are four extant phyla of Deuterostomes-Chordata, Echinodermata, Hemichordata and Xenoturbellida.

The number of cervical vertebrae are seven in almost all mammals including human beings.

The body cavity which is lined by mesoderm is called coelom. Animals possessing coelom are called coelomates, e.g., annelids, molluscs, arthropods, echinoderms, hemichordates and chordates.

Chondrichthyes is one of the classes of super-class-Pisces, sub-phylum-Vertebrata and phylum-Chrodata. The members of class-Chondrichthyes are marine animals with streamlined body and have cartilaginous endoskeleton. Mouth is located ventrally. The skin is tough, containing minute placoid scales. The teeth are modified placoid scales which are backwardly directed, e.g., Dog fish (Scoliodon), saw fish (Pristis), great white shark (Carcharodon), sting ray (Trygort), etc.

The body of annelids is covered by thin moist cuticle. Gaseous exchange occurs through general body surface in most forms. In frogs the breathing is cutaneous, pulmonary and buccopharyngeal. In fishes the breathing is through gills.

The moulting of cuticle in insects usually occurs at a fixed numbers of times. The interval between moults is called a stadium, and the form that an insect takes in any stadium is called an instar.

Class Example Gastropoda Pila (apple snail) Cephalopoda Cuttle fish Pelecypoda Mussel and clam

Turtle (chelone) is an aquatic and marine form belongs to class-Reptilia. Salamander, toad and newt (Triturus) belong to class-Amphibia.