animals with tissue level of organisation. • They have eight external rows of ciliated comb plates (comb jellies) which help in locomotion. • Bioluminescence is well marked in ctenophores. • They lack nematocysts but possess special cells called colloblasts which help in food capture.
• They reproduce only by sexual means. Fertilization is external and development is indirect and includes a larval stage called cydippid larva. Identification: The given specimen is identified as Pleurobrachia. It belongs to the Phylum Ctenophora.
Rostellum Hook Scolex Sucker Neck Immature proglottid Mature proglottid Gravid proglottid Identification: The given specimen is identified as Tapeworm. It belongs to the Phylum Platyhelminthes. XI Std Biology-Zoology Glossary . ASCARIS Reasons for identification: • Ascaris is a roundworm because it is circular in cross section.
• It is a triploblastic, pseudocoelomate animal. • The unsegmented body is covered by a protective layer called cuticle. • Alimentary canal is complete with a well developed mouth, pharynx and anus / cloaca. • Sexes are separate and exhibit sexual dimorphism.
• Excretion is carried out through Rennet glands. • It is an endoparasite. . EARTHWORM Prostomium Segment Anus Peristomium Clitellum Identification: The given specimen is identified as Earthworm.
It belongs to the Phylum Annelida. Mouth Mouth Excretory Pore Excretory Pore Leteral Line Cloacal aperture Penial Spicules Tail Anus Female Gonopore Identification: The given specimen is identified as Ascaris . It belongs to the Phy- lum Aschelminthes. Reasons for identification: • Earthworm is a triploblastic, schizocoelomate animal.
• Its elongated body is segmented. • The longitudinal and circular muscles in the body wall help in locomotion. • The circulatory system is of closed type and the respiratory pigment haemoglobin is present in the plasma. • It is a hermaphrodite animal.
XI Std Biology-Zoology Glossary . COCKROACH Reasons for identification: • It is a triploblastic, schizocoelomate animal. • It has jointed appendages which are used for locomotion. • Body is covered by a chitinous exoskeleton which is shed off periodically by a process called moulting/ecdysis.
• Respiration is through trachea. • Excretion is by