238 Miscellaneous. 



July 23. — Many of the species Natica Montagui. 

 obtained the first day, together Manyelia teres. 



with Lima subauriculata. purpurea. 



Chiton Icevis. Bulla Cranchii ; very fine. 



All the above shells were procured alive, except those specified as 

 otherwise, and some of them are new to that locality. 



I remain, yours most truly obliged, 



W. W. Walpole. 



On the Irritability/ of the Leaves of Drosera rotundifolia. 

 By Dr. Milde. 



Towards the end of June I placed on the middle of a strongly 

 vegetating leaf of a plant of Drosera rotundifolia which I had had 

 for a short time in a cup of moss in my room, four small flies of 

 about the size of a pin's head. The insects remained nearly motion- 

 less upon it, and their efforts to escape from the sticky matter were 

 ineffectual. After about five minutes I again looked at the leaf, when 

 to my astonishment I saw that the glandular hairs of the anterior 

 margin of the leaf, which had been previously extended horizontally, 

 had turned back towards the surface of the leaf and partially covered 

 the flies. I had no time until the following day to observe the leaf 

 again carefully, when I found that the anterior margin and the sides 

 of the leaf had turned over towards its middle and thus completely 

 enveloped the flies. It was only after the lapse of five days that the 

 margins of the leaf and hairs had returned to their places, so as to 

 leave the dead flies lying free on the surface. — Bot. Zeitung, x. 540. 



EMBRYOGENY OF ORCHIS, GESNERIA, AND OTHER PHANEROGAMIA. 



Dr. Cobbold laid before the Edinburgh Physiological Society a 

 brief account of some investigations into the embryogeny of Orchis, 

 Gesneria, and other Phanerogamia. These observations, together 

 with a preliminary account of the labours and opinions of Schleiden, 

 Amici, Brown, Geraud, Griffith, Hofmeister, Meyen, Mirbel, Mohl, 

 Dickie, and about forty others, formed the subject of an essay, written 

 in the summer of 1849. Dr. Sanderson, who at the same time inves- 

 tigated this subject, has since published in the * Annals of Natural 

 History,' an admirable memoir on the embryogeny of Hippuris vul- 

 garisj the facts there recorded being strikingly confirmed by what the 

 author of this paper observed as occurring in the above genera. From a 

 review of the whole matter, the following conclusions are to be drawn : — 



1st. That, prior to impregnation, the ovule always contains an 

 embryo-sac. 



2nd. That the embryo- sac is commonly formed at the apex of the 

 nucleus. 



3rd. That in the interior of the embryo-sac there exists a fluid, 

 more or less granular. 



4th. That the sac frequently protrudes beyond the exostome (ovule 

 tube,— Griffith). 



5th. That in the interior of the sac, prior to impregnation, one or 

 more cytoblasts, or embryonic vesicles, are formed. 



