298 TEANSACTIONS OF THE SOCIETY OF 



of plants recently discovered, which are worthy of remark from having beeu 

 found in regions very remote from those inhabited by all the other species of 

 each family to which they pertain. In the first place, a Dioscorea pyrenaica, 

 a European and Alpine species found in the Pyrenees ; then a Pelargonium, 

 discovered in the chain of Taurus, while almost all the species come from the 

 Cape, except a few species brought from New Holland ; lastly, M. Boissier has 

 recently found a Pilostyle, or a plant of the prickly Astragalus, which was sent 

 to him from the East by M. Hausknecht, botanist. 



Professor de Candolle stated (March 1, 1866) that, in studying the genus Bego- 

 nia, he had recognized therein fifty- seven very natural sub-genera. As a general 

 principle, it will be found that in proportion as the groups of a genus are better 

 established and characterized those groups will be geographically circumscribed. 

 The African species of the Begonia are generally very different from those of 

 other equatorial regions, and particularly from those of Brazil. M. de Candolle 

 therefore deems it probable that the deep cavity which separates America from 

 Africa has existed from very remote geological epochs. 



Zoology. — Dr. Claparede communicated (July 6, 1865) the result of observa- 

 tions which he had recently made on the Rotifers, with a view to explaining 

 the mechanism of their alimentation. He shows that the cilia of the rotary organ 

 do not directly contribute to the afflux of liquids towards the mouth ; they 

 merely generate closed currents, which move in something of an ellipsis perpen- 

 dicular to the plane of the vibratory organ and tangential to the ciliated border 

 of that organ. These currents pass along a groove under the edge of the rotary 

 organ and parallel to that edge. A part of the molecules, carried along by these 

 closed currents, penetrate into the groove, and are thence conducted into the 

 mouth by a row of secondary cilia. This second row of cilia presents, in effect, 

 a contrary movement in the two rotary organs of the Rotifers, and in the two 

 lobes of the single organ in the Melicertse. Among all those of the animals in 

 question in which the rotary organ is double, as in the Rotifers, the apparent move- 

 ment is identical in the two organs ; that is, the inverse of that of the hands of a 

 watch. The mouth being situated between the two organs, it is impossible that 

 both should convey the nutritive particles to the mouth, and yet direct observa- 

 tion shows that the aliments are precipitated from right and left into the buccal 

 orifice. The same contradiction presents itself in the Rotifers with a single 

 organ, but bilobate, with the mouth under the groove ; as, for example, in the 

 Melicertse. The movement, in fact, passes from the right to the left lobe, pre- 

 serving the same direction. It is consequently directed towards the mouth in 

 the first, and away from the mouth in the second ; nevertheless, the nutritive 

 particles flow from the two sides into the mouth. 



The same member, f January 4, 1866,) after having noticed the latest researches 

 of Mecznikoff and Leuckart on the transformations of the Nematoidse, gave a 

 history of the different states of the Ascaris nigrovenosa. He entered also 

 into details on the development of the ' Cucullant' of the pike and the perch, 

 and on that of the ' Olulant' of the cat. 



M. Lunel read a memoir on the genus Brama, (see Mem. de la Societe de 

 Phys. et d'Hist. Nat., t. xviii, p. 165,) a genus of fishes heretofore imper- 

 fectly studied, and on a new species brought from the island of Cuba by H. de 

 Saussure, to which the author has given the name of Brama Saussurei. In 

 this interesting treatise, accompanied with plates and new anatomical details, 

 the author especially sets forth the very remarkable differences presented by 

 the scales in this group of fishes — differences which furnish excellent specific 

 characters. 



M. Victor Fatio, (October 5, 1865,; in speaking of experiments which he had 

 made to verify the kind of utility incident to the cavities of air in the bones of 

 birds, stated that these cavities, though perforated, had not perceptibly affected 

 the faculty of flying. 



