GENEVA SOCIETY OF PHYSICS AND NATURAL HISTORY. 211 



M. de Saussure, in presenting to the society the third part of his 

 studies of the Orthoptera, which is devoted to the family of the GrylUdce, 

 gives a few details of the musical organ with which the males of this 

 family are endowed. The singing is produced by the intercrossing and 

 very rapid friction of the two elytra against each other. He shows the 

 series of transformations that the elytron undergoes in the male to ren- 

 der the production of a sound possible, whereas with the females the 

 elytron remains in the normal state. 



M. Fatio read a memoir on the different development of the pectoral 

 fins in the two sexes among some fish of the genus Cyprinns, which live 

 in the waters of our environs, especially among the minnows. With 

 these fish, particularly in the rutting season, the swelling and develop- 

 ment of some of the Larger rays of the males have the effect of expelling 

 and causiug the disappearance of the smaller rays, so that their num- 

 ber is reduced to ten, and even to six only, while in the female the rays 

 are always very slender and from fourteen to sixteen in number. 



The same member communicated a memoir on a curious case of mela- 

 nism, of nodose melanosis, which is sometimes observed in fish of the 

 genus Ctiprinus, and which is due to the i)reseuce of a small parasite 

 which M. Humbert recognized as a helminth. These two memoirs 

 were published in No. 205 of the ArcMves^ of January, 1875. 



Dr. Fol presented a summary of researches made by himself, on the 

 development of the ^gg of the Medusae and the Pteropodous Mollusks, 

 during his stay at Messina; he studied particularly the mode of formation 

 of the egg-shell of the latter. 



The same member communicated the principal results of the investi- 

 gations to which he had been devoting himself for some years, into the 

 devolopment of the nervous system and the sexual organs of the Mol- 

 lusks. M. Fol studied in the embryos of Pteropods (which more par- 

 ticularly favor these researches), the mode of formation of the nervous 

 system, as well as the organs of hearing and sight. Finally, M. Fol com- 

 municated the results of some observations made by him at Messina, 

 upon the origin of the generative organs, male and female. These in- 

 vestigations led him to adopt the views of M. Ed. Van Beneden on 

 this subject. 



Dr. Prevost presented the results of some experiments he recently 

 made on the physiological properties of the Jaborandi. The eifects pro- 

 duced by an infusion of this plant are quite similar to those produced 

 by the muscarine, consisting in a powerful salivation, and in a general 

 way in an exaggerated secretion of all the glands except the kidneys. 

 Atropine may be considered as antagonistic to this new substance, as 

 well as to the muscarine; it can, in fact, be employed to arrest the sali- 

 vation produced by the two other poisons. 



Independently of these memoirs read before the society, a large num- 

 ber of different communications were made, and reports of discoveries. 



