338 NATURAL SCIENCE. 



JULY, 



is thus an opportune " find." As the result of an exhaustive 

 examination, the author is convinced that not only is the Forest-bed 

 animal specifically identical with the Trogonthere, but likewise with 

 the creature found in the Upper Tertiary of St. Prest, in France, and 

 described under the name of Conodontes. Mr. Newton is also careful 

 to indicate the points in which the skull of the Trogonthere differs from 

 that of the true Beaver {Castor) ; and the points of distinction are so 

 great as to leave no manner of doubt as to the right of the two forms 

 to be at least generically separated. The reason why a widely- 

 distributed animal like the Trogonthere, apparently as well fitted to 

 survive as its contemporaries the Beaver and the Desman, has 

 become extinct, is not yet apparent. 



The scope for the operation of the principle of Natural Selection 

 in a group of organisms so lowly as the Bacteria, may at first sight 

 appear somewhat limited ; but in an article just published by 

 Professor G. Canestrini in the Bull. Soc. Veneto-Trent. Sci. Nat. (vol. v., 

 pp. 85-100), the author points out that the range of possible variation 

 is not so restricted as might be supposed. In the first place, the 

 diminution in size of the organisms may count as an advantage ; and 

 the possible modes and manners of locomotion are sufficiently multi- 

 farious. The varying development of protective membranes and 

 capsules may, in the Professor's opinion, afford much scope for the 

 effective agency of Natural Selection — and so also may the numerous 

 variations in the form, size, and capability of resistance of the spores. 

 On the whole, it seems probable that Bacteria originated primitively 

 as organisms living in the air ; and, if that be the case, there are 

 thus endless possibilities of modification (at least physiologically) as 

 they become adapted for life respectively in animal tissues or 

 fermenting and putrefying liquids. In any case, whatever be the 

 modus operandi of the evolution, remarkable new forms are continually 

 being discovered, and attention may be particularly directed to the 

 newly-established genus Nevskia, found by Dr. A. Famintzine in the 

 aquarium of the Botanical Laboratory of the Imperial Academy at 

 St. Petersburg [Bull. Acad. Imp. Sci. St.-Petersb., n.s., vol. ii.. No. 3). 

 Nevskia ramosa is believed b}' its discoverer to be the first representa- 

 tive among the Schizomycetes of the colony- forming organisms with 

 branched processes, of which the corresponding forms have long been 

 known among Algae and Infusoria. 



The *' Societe Scientifique du Chili," founded by a group of 

 French residents in April, 1891, has issued the first fascicle of its 

 " Actes." This is a work of 185 pages illustrated by 18 plates. 

 The longest memoir is by M. F. Lataste, and is an "Etude sur la 

 faune chilienne," and of it two parts have been issued dealing with 

 the Lizards and Bats. The President of the Society, M. Obrecht, 



