PARAMECIUM (often misspelt Paramaecium, Paramoe cium), the slipper animalcule, a genus of aspirotrochous ciliate Infusoria (q.v.), characterized by its slipper-like shape, common in infusions, especially when they contain a little animal matter. It has two dorsal contractile vacuoles, each receiving the mouths of five radiating canals from the inner layer of the ectosarc, and a large ovid meganucleus, and one or two micronuclei. From its abundance, the ease with which it can be cultivated and observed, its simple structure and large size in.), it is frequently select ed for elementary study and demonstration, as well as for research.
P. bursaria is green, owing to the presence of symbiotic algae. PARANA, a State of southern Brazil, on the Atlantic coast, with the Parana river as its western boundary line. Area, 77,160 sq.m.; pop. It includes two dissimilar regions—a, narrow coastal zone, thickly wooded, swampy, and semi-trop ical and a plateau (2,500 to 3,00o ft.) whose precipitous, deeply eroded eastern escarpments are known as the Serra do Mar, or Serra do Cubatao. The southern part of the State is densely forested and has large tracts of Paraguay tea (Ilex para guayensis), known in Brazil as herva mate, or matte. The plateau slopes westward to the Parana river, is well watered and mod erately fertile, and has a remarkably uniform climate of a mild temperate character. The larger rivers of the State comprise the Paranapanema and its tributaries the Cinza and Tibagy, the Ivahy, Piquiry, Jejuy-guassil, and the Iguassii with its principal tributary the Rio Negro. Twenty miles above the mouth of the Iguassu are the Iguassu falls, 215 ft. high. The plateau is undu lating and the greater part is adapted to agriculture and pastoral purposes. There are two railway systems in the State—the
Paranagua to Curityba (69 m.) with an extension to Ponta Grossa (118 m.) and branches to Rio Negro (55 m.), Porto Amazonas (6 m.) and Antonina ( io m.) ; and the Sao Paulo and Rio Grande, which crosses the State from north-east to south west from Porto Uniao da Victoria, on the Iguassil, to a junction with the Sorocabana line of Sao Paulo at Itarare. The upper Parana is navigable between the Guayra, or Sete Quedas, and the Urubu-punga Falls. The chief export of Parana is Paraguay tea.
There is a large foreign element in the population owing to immigrant colonies on the uplands, and progress has been made in small farming. Besides ithe capital, which is Curityba, the princi pal towns (with the population of their municipal districts for 1920) are Paranagua (18,998) ; Antonina, at the head of the bay of Paranagua (10,105) ; Campo Largo, 20 m. W. of Curityba (19,149) ; Castro, north-north-west of the capital on the Sao Paulo and Rio Grande line (18,949) and Ponta Grossa (20,171), at the junction of the two railway systems of the State.
Parana was settled by gold prospectors from Sao Paulo and formed part of that captaincy and province down to 1853, when it was made an independent province. The first missions of the Jesuits on the Parana were situated just above the Guayra Falls in this State and had reached a highly prosperous condition when the Indian slave hunters of Sao Paulo (called Mamelucos) com pelled them to leave their settlements and emigrate in mass to what is now the Argentine territory of Misiones.