Difference between revisions of "Pseudophyllidea"
(New page: Pseudophyllidean tapeworms have a scolex with four longitudinal grooves. They have a genital pore which is centrally placed on each segment. The eggs and life-cycle have some similarity to...) |
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| − | Pseudophyllidean tapeworms have a scolex with four longitudinal grooves. They have a genital pore which is centrally placed on each segment. The eggs and life-cycle have some similarity to that of the trematodes. Pseudophyllidean egg shell is thick, brown and operculate. The Pseudophyllidean life-cycle uses two intermediate hosts – the coracidium, which emerges after hatching, must first be ingested by a crustacean. A larval procercoid develops within the body cavity of the crustacean. If the crustacean is then eaten by a freshwater fish, the procercoid is liberated and develops into a second larval stage, a plerocercoid, within the muscles of this new host. The plerocercoid possesses the characteristic scolex – it is only this stage that is infective to the final host. There are no pseudophyllideans of importance in the UK, but some are of significance in tropical or sub-tropical areas (for example Spirometra), and in sub-arctic regions (for example Diphyllobothrium). | + | Pseudophyllidean tapeworms have a scolex with four longitudinal grooves. |
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| + | They have a genital pore which is centrally placed on each segment. | ||
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| + | The eggs and life-cycle have some similarity to that of the trematodes. | ||
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| + | The Pseudophyllidean egg shell is thick, brown and operculate. | ||
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| + | The Pseudophyllidean life-cycle uses two intermediate hosts – the coracidium, which emerges after hatching, must first be ingested by a crustacean. A larval procercoid develops within the body cavity of the crustacean. If the crustacean is then eaten by a freshwater fish, the procercoid is liberated and develops into a second larval stage, a plerocercoid, within the muscles of this new host. The plerocercoid possesses the characteristic scolex – it is only this stage that is infective to the final host. | ||
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| + | There are no pseudophyllideans of importance in the UK, but some are of significance in tropical or sub-tropical areas (for example Spirometra), and in sub-arctic regions (for example Diphyllobothrium). | ||
Revision as of 20:49, 21 December 2008
Pseudophyllidean tapeworms have a scolex with four longitudinal grooves.
They have a genital pore which is centrally placed on each segment.
The eggs and life-cycle have some similarity to that of the trematodes.
The Pseudophyllidean egg shell is thick, brown and operculate.
The Pseudophyllidean life-cycle uses two intermediate hosts – the coracidium, which emerges after hatching, must first be ingested by a crustacean. A larval procercoid develops within the body cavity of the crustacean. If the crustacean is then eaten by a freshwater fish, the procercoid is liberated and develops into a second larval stage, a plerocercoid, within the muscles of this new host. The plerocercoid possesses the characteristic scolex – it is only this stage that is infective to the final host.
There are no pseudophyllideans of importance in the UK, but some are of significance in tropical or sub-tropical areas (for example Spirometra), and in sub-arctic regions (for example Diphyllobothrium).