Scientific Intelligence. — Zoology. 389 



of the insects, or from their webs being lighter than the air, 

 Mr Blackwall states, that the ascent of gossamer takes place 

 only in serene bright weather, and is invariably preceded by 

 gossamer on the ground. He then details the phenomena of a 

 remarkable ascent of gossamer, October 1, 1826, when, a little 

 before noon, the ground was everywhere covered with it, the 

 day being calm and sunny. A vast quantity of the fine shining 

 lines were then seen in the act of ascending, and becoming at- 

 tached to each other in various ways in their motion, and were 

 evidently not formed in the air, but on the earth, and carried 

 up by the ascending current, caused by the rarefaction near the 

 heated ground ; and when this had ceased in the afternoon, they 

 were perceived to fall. An account is added of two minute 

 spiders that produce gossamer, and of their mode of spinning ; 

 and particularly when, impelled by the desire of traversing the 

 air, they climb to the summits of various objects, and thence 

 emit the viscous threads in such a manner, as that it may be 

 drawn out to a great length and fineness by the ascending cur- 

 rent, until, feeling themselves sufficiently acted upon by it, they 

 quit hold of the objects on which they stood, and commence 

 their flight. Some of these insects, which were taken for the 

 purpose of observation, when exposed to a slight current of air, 

 always turned the thorax to the quarter from whence it came, 

 and emitted a portion of glutinous matter, which was carried 

 out in a, line. 



33. Identity of the two nominal Species of the Ornithorynchus. 

 — In a memoir printed in the Annates des Sciences Naturelles 

 for December 1826, M. Geoffroy St Hilaire proves, from facts 

 observed by him in a number of individuals of ornithorynchus, 

 that the pretended specific characters taken from the red or brown 

 colour of the hair, or the relative size of the spur in the male, 

 are of no value, the circumstances on which they are founded 

 being irregular, and indicative merely of individual differences. 



34. Glandular Apparatus^ lately discovered in Germany, mi 

 the Abdomen of the Ornithorynchus. — M. Geoffroy St Hilaire, 

 in a paper in the Annates des Sciences Naturelles, December 

 1826, denies that the gland discovered by Meckel, and consi- 

 dered by him as the mammary gland of the ornithorynchus, is 

 a true mammary gland. He founds his opinion on the organisa- 



