Cestodes

General Characteristics
Flat, ribbon-­‐ like White or yellowish Dorsoventrally flattened

Few mm to several meters

Sexes are not separate

General Characteristics
Adults are found in the intestinal tract of man Body cavity and alimentary cavity are absent

Excretory and nervous systems are present Complete reproductive system is present in every proglottid

Regions in Adult Worm
Scolex
Head Suckers Hooks

Neck

Strobila
Body trunk Proglottids

Types of Proglottids
Immature
Male and female organs are not differentiated

Mature
Male and female organs have become differentiated (male organs appear first)

Gravid or ripe
Uteri are filled with eggs (other organs have atrophied or disappeared)

Differences
Points of differences Pseudophyllidean Cyclophyllidean

Scolex

Strobila

Spoon-­‐shaped with slit-­‐like sucking grooves called bothria, no hooklets Anapolytic Do not shed segments

Quadrate, with 4 cup-­‐like suckers with or without rostellum Apolytic Shed segments

Differences
Points of differences Gravid proglottid

Pseudophyllidean Cyclophyllidean

Pore

All reproductive All reproductive organs are present organs degenerate Uteri coils in rosette except uteri form Uterine pore Genital pore Median ventral Lateral margin of surface proglottid

Differences
Points of differences Ova

Pseudophyllidean Cyclophyllidean

Oval operculated immature Coracidium procercoid plerocercoid or sparganum

Larval stages

Spherical non-­‐ operculated embryonated Cysticercoid cysticercus hydatid

Differences
Points of differences Intermediate host

Pseudophyllidean