Nalural'Historical Collections, 457 



Mines of Silver or Argentiferous Lead in the Caucasus, — Dr. Meyer, a mem- 

 ber of the scientific expedition sent to the Caucasus by the Imperial Academy of 

 Sciences of St. Petersburg, has informed the Academy that M. de Engelhardt 

 believes he has found in the Caucasian mountains, about 120 versts from the 

 fort Grosnaia, rich mines of silver or of argentiferous lead, on whose existence the 

 academician Hamel made a communication to the Academy last year. — Bull, de 

 Soc. Geog. May, 1830. 



Seat of the Seme of Touch — The presence in insects of the ganglion which 

 represents the brain, is not absolutely necessary for the existence of the sense of 

 touch. After decapitation they feel on the surface, and in their limbs, by means 

 of their other ganglions, such impressions as may be made on them. The 

 spinal marrow of reptiles, young birds, and young mammiferous animals, seems 

 also capable, after the destruction of the brain, of being modified by irritations, 

 of feeling them, and of occasioning, in consequence thereof, durable and calculat- 

 ed movements, which are not to be confounded with those convulsive and fuga- 

 cious motions that are attributable solely to irritability. M. Calmeil thinks that 

 this faculty of the spinal marrow is probably diffused throughout its whole extent. 

 Further, it is probable that in the natural state of our functions the brain is the 

 ■ole centre of irritability, and that the spinal marrow only becomes sensible when 

 the brain ceases to exist. The co-ordination of our voluntary motions is doubt- 

 less attributable only to the brain. — Med. Journ. quoted in Brande's Journal, 

 No. XIV. 



Extracts from the Analysis of the labours of the Academy of Sciences during 

 the year 1826 ; by Baron Cuviek. Paris, 1830. 



Zoology Continued. — Hebenstreit on a new kind of Silk The Academy 



has received a communication through M. Lenormand, of a curious observation 

 of M. Hebenstreit, Professor at Munich, on the possibility of obtaining silk of 

 any size, and of unequalled texture, from the larva of the tinea of the Prunu^ 

 Padus (St. Lucia-wood). This little insect, scarcely 6 lines long, spins con- 

 stantly as it is moving about, and weaves amongst the twigs of the sort of awn- 

 ing under which it seeks shelter. If we place a great number of them on a 

 sheet of paper under a glass bell, they speedily cover the surface with a web so 

 fine that the least motion of the air, the heat alone of the hand, destroys it. The 

 web is quite homogeneous and particularly white ; but its extreme delicacy does 

 not permit the hope that it can ever be employed for useful purposes. 



MM. Audouin and Milne Edwards on a new genus of Crustacea (Nicothoa). 



MM. Audouin and Milne Edwards have discovered on the lobster a little parasi- 

 tical animal of the class Crustacea, which to the unassisted sight presents nothing 

 but a body divided into four lobes or articulations. With the microscope we 

 perceive that the first pair of these lobes is a development of the corselet, and 

 that the second is composed of ovaria. Between the lobes of the corselet is a 

 little obtuse head, bearing superiorly two eyes and two antenna, and below the 

 jaws, five pairs of feet. Between the two ovaries is a little jointed tube, termin- 

 ating in hairs. These young naturalists have formed a genus of this anima!, 

 which they call nicothoa. This parasite is always very firmly attached to the fi- 

 laments which compose the branchia- of the lobster. No excitation can make it 

 leave loose ; it will rather be torn to pieces ; if we plunge the lobster into a dele- 

 terious liquid, still the nicothoa will not abandon its hold. Even when it is de- 

 tached, it remains immoveable, though the motion of its internal fluids proves 

 ihat it continues to live. But it cannot always have been in this state : when it 

 passed out of its egg, it must have sought for a lobster, and on this lobster, for a 



