(b) Locomotiva: Hydra, Pennatula, Taenia, Volvox, Furia, Chaos.
2.- Various Forms of Tapeworms. A, Taenia echinococcus; X 12 (from Leuckart).
- Anatomy of Taenia (from Leuckart).
A, portions of Taenia saginata; X 2.
Taenia echinococcus has only three, Echinobothrium four, Bothriocephalus three thousand.
The minute Taenia (Davainea) proglottina (5 to I mm.
Man himself, as well as other mammals, is the intermediate host of the dangerous parasite, Taenia echinococcus, in countries where cleanliness is neglected; the pig is the host of Taenia solium, and other cases may be seen from the table at the end of this article.
- Development of Taenia (from Leuckart).
Of all parasites the one which by its mere presence is the most dangerous is the larva of Taenia echinococcus.
The tapeworm, Taenia saginata, throws off eleven proglottides a day during its mature stage, and if this rate of increase were maintained for a year the total weight of its progeny would be about 550 grammes.
- For practical purposes we have only three varieties of tapeworms to deal with as inhabitants of the human alimentary canal: Taenia saginata, the beef tapeworm; Taenia solium, the pork tapeworm; and Dibothriocephalus latus, the fish tapeworm.
Comparatively uncommon in Western Europe, the Taenia saginata is common in Eastern Europe, Asia and South America.
The tapeworm most frequently found in man in Western Europe is the Taenia solium, which is constant wherever pork is consumed, and is more common in parts where raw or imperfectly cooked pork is eaten.
In the Taenia solium it takes 3 to 3z months from the time of ingestion of the embryo to the passage of the matured segments, but in the Taenia saginata the time is only about 60 days.
The segments of the Taenia solium are usually given off in chains,.
Those of the Taenia saginata singly.
The embryo of the taenia echinococcus finds its way from the stomach or intestine into a vein passing to the liver, and, settling itself in the liver, causes so much disturbance there that a capsule of inflammatory material forms around it.