Linnaan Society. 195 



the height of an inch from the base of the stem, the cells are filled 

 with fluid only, and each cell contains a cytoblast with its contents 

 presenting a milky hue. Carrying on the sections from above down- 

 wards within these limits, the cells are first found to become more 

 transparent and to contain granules with well-defined outlines ; lower 

 down they exhibit minute granules mixed with the fluid of the cell, 

 leaving the cytoblast transparent, empty and angular ; while at the 

 base the granules have arrived at their perfect condition and the 

 cytoblast is no longer visible. Thus it appears, Mr. Quekett states, 

 that there are two modes of formation of starch connected with the 

 cytoblast ; in the one case the cytoblast becomes a nucleated cell 

 and the grains originate on its exterior ; in the other it does not be- 

 come a nucleated cell, but gives origin to the grains in its interior. 



As regards the origin of chlorophylle, Mr. Quekett states that in 

 the plants which he has examined the same mode of development ap- 

 pears to obtain as described in the formation of starch, viz. the gra- 

 nules originating from a nucleated cell, and instances the cuticle of 

 the very young frond of Scolopendrium vulgar e t L., as an example ; 

 but he adds that the first origin of chlorophylle is so mixed up with 

 the formation of the cell, that it is impossible to arrive by dissection 

 at the commencement of the process. 



May 5. — The Lord Bishop of Norwich, President, in the Chair. 



Read a letter " On the Migration of the Swallows," addressed to 

 the Secretary. By Thomas Forster, Esq., M.D., F.L.S. &c, dated 

 Bruges, May 2nd, 1846. 



The object of this note is to show, not only that the four British 

 species of Swallows migrate, but also that their migration is pro- 

 gressive through Europe to Asia and Africa. The first table is stated 

 to have been compiled from the recorded observations of naturalists 

 and others, copied on the spot during an extensive tour through 

 Europe in the years 1833, 1834, 1835 and 1836. Dr. Forster states 

 that he is satisfied that numerous flights of the several species an- 

 nually arrive at the end of February and beginning of March in Sicily, 

 Italy and the Islands of the Mediterranean, from Africa. Of these 

 a portion proceed after a few days' rest towards the north, leaving 

 colonies in different places as they advance, until they reach their 

 most northern destination in Europe. In autumn they retire in the 

 same manner, and their numbers appear prodigiously increased in 

 particular places where they halt and rest for days before the phalanx 

 again takes wing. This, Dr. Forster states, is also the case with 

 Quails, with the Mountain-Finch, and with many of the Warblers. 

 Particular places seem to be favourite resorts as resting-places to 

 particular species, as Pisa for example to the Swift, the Campagna 

 and Southern Italy to the Martin. When an early spring has oc- 

 curred in the S. of Europe, these birds have made their appearance 

 earlier, as if they had been capable of inferring an earlier season 

 northwards. 



P2 



