29 O TRANSACTIONS OF THE SOCIETY OF 



to light numerous fossils in a state of remarkable preservation, among others the 

 Nerit07na sinuosa, (Morris,) which is very abundant. (See Memoir de la Soci^te 

 de Phys. et d'Histoire Nat., tome xix, first part.) 



M. Ohaix communicated (April 5, 1866) his observations on ilie volcanic 

 rock of the left hank of the Rhine, near Aridernach. This rock, which he has 

 traversed and studied, extends over a surface of 7| leagues from north to south, 

 by 3|- leagues from east to west. Thirty cones, rounded at the summit, are the 

 craters of as many extinct volcanoes, rising to a mean level of 700 feet above 

 the surrounding inhabited places, which last are 500 feet above the sea. The 

 plains are formed of deep beds of cinders, lapilli and volcanic tufas. At more 

 than 100 feet below these deposits a thick bed of basaltic lava is worked, near 

 Niedermending, for mill-stones. In the centre of the volcanic region the lake 

 of Laach, circular in its form, has a surface of 338 hectares, a depth of 177 feet, 

 and a level of 847 feet above the sea, since the construction of a subterranean 

 drain has reduced it by 18 feet. Besides this lake, thirty ancient craters may 

 be counted, which have been convei'ted into lacustrian basins, more or less dried, 

 and especially numerous in a second volcanic region lying more to the west than 

 the first, and to the north of Treves. 



Botany. — M. Marc Micheli communicated (July 6, 1865) observations on the 

 stamens in the fainily of the Ericacece. In some species of this family the sta- 

 mens are provided with appendages of very variable forms ; these are sometimes 

 long awns, sometimes membranaceous awns, sometimes simply small strumse. 

 He has found that, when observed with the microscope, whatever their outward 

 appearance, their internal structure is always the same. Under a layer of 

 epidermis is seen a certain quantity of spiral cells. The tissue which these form 

 is prolonged to a certain distance along the walls of the loculaments of the 

 anther, 'i'he distribution of the appendages in the species and tribes of the 

 family follows no rule. Two neighboring kinds or species may differ in this 

 respect. 



Si. Duby, (October 15, 1865,) with reference to a champignon of the vine, 

 on which he read a notice thirty-one years ago, said that he had never met with 

 it since then, but that this year it is very abundant. MM. de Candolle and 

 Muller are inclined to ascribe the development of its spores to the drought which 

 has prevailed. M. Duby, in giving an account of the new researches of MM. 

 Bary add Allie on the Mucedineae, recalled the fact that when the spores of the 

 Mitcor mncedo are sown on different substances, completely different forms are 

 seen to be developed in the resulting mouldiness, which have been classed here- 

 tofore as different species. It is probable, therefore, that more than twenty 

 species of Mucedineae should be suppressed. These same spores, sown in water, 

 may even produce algae. In support of these observations. Professor de Can- 

 dolle added that his father had already remarked, at Annonay, that the cham- 

 pignons which were developed on old rags or waste scraps varied according to 

 the origin of those articles. At Paris, the dealers in cheese had assured him that 

 the mouldiness varied according to the part of France from which the cheese was 

 brought. 



Dr. Muller (November 2, 1865) entered into some details on the inflorescence of 

 the genus Dalecampia. This inflorescence is composed of a general involucrum 

 formed by three pairs of decussated bracteae. The involucrum encloses flowers of 

 two sexes. After having described with care the position of the female auu 

 male flowers, M. Muller compares this inflorescence with that of the genus Eu- 

 phorbia, the involucrum of which is quincuncial, and shows by diagrams that in 

 the Euphorbias the relative position of the two sexes presents the contrary of 

 what exists in the Dalecampias, the summit in the former being occupied by a 

 female flower and not by male flowers. In comparing the male flower of the 

 Dalecampia, which is polyandrous, and provided with a calyx and an articulated 

 pedicle, with the male flowers of the Euphorbias, which are monandrous and 



