NATURAL HISTORY OF GENEVA. 171 



In his researches upon the bottom of Lake Lemau, Profes.sor Forel ex- 

 tracted from the superticial stratum of the ooze, at depths of from 82 to 

 100 feet, and even to the maximum of 980 feet, different crustaceans 

 and other animals which are at present the object of special study with 

 certain naturalists. To his great surprise he found sonje living limnaians 

 (a family of mollusks) at so great a depth that they could breathe but very 

 little oxygen, and that only in the manner of aquatic animals. These 

 same limnajans, wiien placed in an aquarium, developed organs for aerial 

 respiration. 1 



M. Henri de Saussure communicated to us the results of his study of 

 the Orthojjtera, just published in the second part of volume vi of the 

 French Expedition to Mexico. In connection with Gryllides he men- 

 tions the genus Tridacttjius, in which each individual may have three 

 modes of living — subterranean, aerial, and aquatic. A species of the 

 south of France is found also in the sands, sometimes submerged, of 

 the islands of the Khone near Colouges, where M. de Saussure has seen 

 them alive. The two anterior claws serve for burrowing, the middle 

 pair for walking, and the posterior pair for leaping, even when resting 

 upon the water. The animal can rise in leaping to two hundred times 

 its own length. It can also swim. 



Dr. Fol presented a memoir in French, which he has just published in 

 German in the Jenaische Zeitschrift, upon the evolution of C(£le)iterates, 

 in particular upon the egg of the species called Geryonia fungiformis. 

 This work recalled to us by its nature, and by the beautiful plates 

 which accompanied it, those of our eminent and regretted colleague, 

 Edouard Claparede. The egg of the Geryonia passes by a regular 

 segmentation to the state of the morula, then by means of a doubling of 

 the single cellular stratum it produces two spheres, one fitting into the 

 other, which become the ectoderm and endoderm. This formation, of 

 which the author observed the course, appeared to him to differ much 

 from that of the other cases, in which the double stratum results from 

 the invagination of the primitive sphere. The conception of Leuckart 

 and Hcieckel, of two subkingdoms having their common origin in the 

 Protozoaires, finds support in these facts. M. Fol also examined the 

 question whether there exist animals which in the adult condition are 

 constructed like the ogg of the superior animals in the first phases of its 

 evolution. He pointed out, in this connection, the Protomoyxa^ which 

 was mentioned by M. Uieckel, and the Megasphcv> a plamda. 



M. Gustave Rouchette has continued the curious observations made 

 by M. Moggride at IMentone, upon various species of ants and spiders. 

 He showed us the seeds which the ant, called Atta Barbara, accumulates 

 for food, in small subterranean cavities. When one of these seeds com- 

 mences to germinate, the ants cut off the root and carry the seed into 

 the sunshine to dry the w^ound. The mason spiders, which live in a 



1 See the articles of M. Forel upon the fauua of the deep waters of the lake, in the 

 Bulletin de la Soc. Vaudois6 des Sc. Nat., xiii, No. 72. 



