592 Zoology, 



distinguished eight muscles by name, and disclosed numerous 

 additional facts of great value. 



In their generative system, he has proved the existence of 

 all three modes of generation ; the viviparous, the oviparous, 

 and the gemmiparous. Some species of the animals are 

 hermaphrodite. Besides clearly demonstrating these three 

 systems (the digestive, the muscular, and the generative,) to 

 exist in these minute beings, Ehrenberg conceives that he 

 also discovers in them a vascular and a nervous system : but 

 the two latter are not considered as yet clearly demonstrated. 



Professor Ehrenberg, in his travels in Siberia, found several 

 new genera and species of infusory animalcules, which have 

 already been alluded to in our Vol. IV. p. 255. 



In consequence of these most remarkable and important dis- 

 coveries in the anatomy of these animated atoms, a totally new 

 classification of them has been elicited. Previously, the appa- 

 rently homogeneous tissues of these minute beings furnished 

 no distinctive characters except the varieties of external form, 

 the presence or absence of ciliae and other appendages ; which 

 are so uncertain, and so changeable, that they have been long 

 ago rejected from other departments of zoology as the funda- 

 mental bases of division. Dr. Ehrenberg now forms a classi- 

 fication of them according to their organisation. To follow 

 him through his classes, orders, families, sections, and genera, 

 would lead us too far. For the examination of these, we refer 

 the reader to the January number of the journal quoted ; 

 venturing to remark that the scheme of classification there 

 exhibited (p. 82 — 86.) seems characterised by the deepest 

 and most patient investigation, by clearness of contradistinc- 

 tion, and by ability of expression. Dr. Gairdner remarks 

 that Ehrenberg has " included under his categories those 

 genera or species oz/Zj/, whose digestive organs he has demon- 

 strated himself by his new method of observation." A plate 

 (pi. iv.) exhibits magnified figures and dissections of Monas 

 termo and atomus Miiller, Leiicophrys patula E/ir., and Hy- 

 datina senta Ekr. ; and displays the wonders of their intestinal 

 structure and general organisation. 



The geographical distribution of these beings, invisible to 

 our unaided sight, is the next and last part of the subject dis- 

 cussed. It occupies twelve pages, and is replete with interest. 

 Dr. Ehrenberg has prosecuted his researches on this subject 

 (as well as on others) in extensive journeys in Africa and 

 Arabia, and in Russia, Siberia, and the Altai' mountains; 

 and he has discovered species in the subterranean waters of 

 the silver mines of these mountains, at the depth of 56 fathoms. 



