Zoo-Lab (Sem-1) - Exercise 12: Phylum Platyhelminthes

Phylum Platyhelminthes

flat worms; body, dorso-ventrally; with bilateral symmetry; triploblastic; examples include Planaria and other free-living flat worms, flukes, and tapeworms

Turbellaria; Trematoda; Cestoda

representative classes of Phylum Platyhelminthes

Class Turbellaria

free-living flatworms and move by means of their ciliated epidermis

Dugesia sp.

Planaria; found in all freshwater habitats that flow slowly; most abundant during December to January; bilaterally symmetrical; moves by means of cilia

melanin

color pigment which causes difference in color values in parts of the Planaria; dorsal portion is darker as opposed to the ventral portion

eyespots

part of Planaria; a pair of eyes at the anterior end

auricles/earlobes

part of Planaria; at the lateral side of the head formed by the extension of the sides

pharynx

part of Planaria; on the ventral side of the body directed posteriorly

mouth

part of Planaria; on the posterior end of the pharynx

intestinal diverticula

part of Planaria; subdivisions of main intestinal branches

anus

an organ that Planaria lack

Class Trematoda

parasitic flatworms with a digestive tract; often with complex life cycles involving two or more hosts

Chlonorchis sinensis

Trematoda; human liver fluke

Schistosoma japonicum

Trematoda; blood fluke

Fasciola hepatica

Trematoda; sheep liver fluke

Class Cestoda

parasitic flatworms with suckers and lack a digestive tract; the body is long with many segments called proglottids

Taenia solium

Cestoda; pork tapeworm

Taenia saginata

Cestoda; beef tapeworm

free-living

animals that are neither parasitic, symbiotic, or sessile