Prof. Ehrenhergs Researches on the Iiifusoria. 87 



IV. Geographical Distribution. 



No sooner is the organized structure and physiological im- 

 portance of the class of infusory animals distinctly recognised, 

 than their geographical distribution becomes a subject of inte- 

 rest, and the question presents itself : 



" Whether the forms of infusory animals, which fill the wa- 

 ters of the earth in such . countless numbers, and which, with 

 many, form the germs of organic life, are thie same in all quar- 

 ters of the world ? Or whether a climacteric difference can be 

 observed to exist between these minute living bodies, correspond- 

 ing to that subsisting between the larger animals ?" 



The subject is not altogether new, although all former obser- 

 vations were isolated^ imperfect, and contradictory. Gmelin, in 

 the 13th edition of the Sy sterna Nature, describes two species 

 of the genus Vorticella, one peculiar to the Atlantic, the other 

 to the Indian Ocean. It is very difficult to decipher the ani- 

 mals to which he alludes. It is certain, however, that they are 

 not Vorticellae ; and it is very doubtful if they are infusoria at 

 all. Riche, in 1791, on d'Entrecasteaux's Voyage in search of 

 Lapeyrouse, made a few observations on the infusoria of the 

 Pacific Ocean ; and Bosc, in 1802, on those of North America ; 

 but both these observers, from their imperfect means of obser- 

 vation, either mistook the larvae of Entomastraci for infusory 

 animals, or came to the conclusion that they did not differ from 

 those of Europe. Chamisso, in Kotzebue's voyage round the 

 world, in 1815, made a few observations on the coast of Brazil, 

 on the animal to which the sea owed its green colour, which he 

 described under the name of the Paramecium oceanicum : it is 

 closely allied in form to the Cercaria viridis. 



M. Ehrenberg has had opportunities of furnishing a few data 

 for the solution of the question during the two very extensive 

 journeys which he has made into the three quarters of the old 

 world ; the first in company with Dr Hemprich into Africa and 

 Arabia ; the second very lately with Baron Alexander Humboldt 

 into Russia, Siberia, and the Altayan Mountains. During both of 

 these journeys he prosecuted with indefatigable industry his ob- 

 servations on these microscopic creations, wherever opportunity 

 offered ; though, from their inferior importance, they were ne- 



