112 Zoological Collections, Invertebrata. 



Ehrenberg*s Researches on the Infusoria At a meeting of the Academy 



of Sciences of Paris, in October last, Baron Humboldt gave a brief notice 

 of a work just published in German by his fellow traveller, M. Ehrenberg, 

 entitled " The Organization, Classification, and Geographical Distribution 

 of the Infusoria in Africa and the north of Asia." '* The number of 

 species," M. de Humboldt remarked, " which were observed during the 

 course of our travels between the Caspian Sea, the Ural, and the Altai, 

 amount to 113, of which eight belong to new genera. By feeding these 

 gelatinous and translucid beings with indigo and carmine, M. Ehrenberg has 

 been able to colour their mouth, stomachs, and the extremity of their 

 alimentary canal, and by thus painting them, as it were, internally, in red and 

 blue, to detect the extreme complication of their organs. In examining 

 the eight plates in Ehrenberg's work, a single glance will show the astonish- 

 ing com.plexity of these beings, many of which, however, do not exceed 

 l-2000th of a line in length. The author employed a Chevallier micro- 

 scope, and generally a magnifying power of 80 diameters. He now 

 publishes the results of ten years' observations, the accuracy of which is 

 increased by his long use of the microscope and micrometer in examining 

 the structure of the mollusca of the Red Sea. The smallest, and what 

 have been considered the most simple Infusoria, are all provided with a 

 mouth and organs of nutrition, and sometimes from thirty to forty stomachs. 

 They all seize their prey, and feed on solid substances. In the monas-termoy 

 which is only 1-1 500th of a line long, we may distinguish four stomachs, 

 a mouth, and ciliae surrounding the mouth. The Vorticellce, Leucophrcey 

 and the Paramcecia, have a more complicated structure. The number of 

 eyes varies in the Rotifejce, in the genera Euglena and Eosphora. But 

 what most attracts the attention of those who occupy themselves with 

 microscopic anatomy, is the complication of the muscular and nervous 

 systems, of the mouth furnished with cartilaginous teeth, and of the organs 

 of nutrition and generation in the Hydatina senta, (Vorticella senta, Miiller,) 

 as presented in the eighth plate of this work. The Academy will doubtless 

 condescend to examine the anatomical portion of this memoir, and the 

 classification of the Infusoria, according to their internal organization, 

 especially the parallelism of the nuda and loricata, (naked, and covered with 

 shields,) which characterizes the whole of this class. M. Ehrenberg 

 discusses the genera which have been established upon other principles, and 

 finds, that individuals of the same species, in different degrees of distension, 

 according to the absence or presence of food in their interior, have been 

 described as distinct genera. He has often observed the Infusoria pass out 

 from the ova, and no direct observation has led him to admit either a 

 spontaneous generation, or an agglomeration of Infusoria, to form the rudi- 

 ments of vegetables and animals. He thinks that all the Infusoria move 

 about during life, and separately seek their food. Of the 113 species 

 observed and described during the course of our travels, 31 species belong 

 to Europe, and 82 to Asia ; but of the species collected in Asia, two-thirds 

 are also observed in central Europe. The Kolpoda cucuUus seems to be the 

 most generally distributed : M. Ehrenberg found it from Mount Sina'i to 

 Dongola, near Berlin, at St Petersburg, in the north. of the Ural, and at the. 

 foot of the Alta'i. In the mines of Siberia, (Soimonofskoi and Schlangen- 

 berg), three species of monad were found, and again the Kolpoda cucullusy 

 at a depth of 6Q fathoms, in places entirely deprived of light. The Infusoriay 

 in their structure, form two natural classes of animals, inhabiting the sea 

 and the land. Some species are found, which (like cryptog amice) are 

 identical under the most opposite latitudes ; they appear to vary, according 

 to the climates, more from Europe to Dongola, than from east to west, 

 from Berlin to the Altai. The salt waters of the Asiatic steps present no 

 very peculiar forms. The dew, examined with the greatest care, in the 



