XX 
INTRODUCTION. 
\ 
The manner in which the feeds of the Horfetails are dif- 
charged is beautiful, and well deferves our regard. The 
laborious and ingenuous Hedwig has well illuftrated this par¬ 
ticular, by a number of figures, in his Theoria PL Crypt, 
^ab. I, 2. And I have found the truth of his Obfervations 
by examining the fame fubjefts, under the firft magnifier of 
Cuff’s Compound Microfcope, as now fold by Nairn and 
Plounty in London ^ my figures, however, vary a little from 
thofe of Hedwig. 
In the annexed Plate, A, is a fingle fhield feparated from 
the flower fpike, and magnified with its curved fupport, and 
its fix feminal valves unopened. Thefe valves open by a lon¬ 
gitudinal future from top to bottom, on the inner fide, and 
copioufly difcharge a foft downy powder, which when newly 
fallen or fhook out may, through a moderate fpy-glafs, be 
feen to fkip and leap about as if alive ; after the difcharge of 
this powder the feminal valves or capfules remain for fome 
time in an horizontal direction, empty and dry, as is ex- 
prefled at B 5 where the underfide of the Ihield and the infide 
of the valves are reprefented. 
The feparate feed-veflels, if fuch we may call them, con- 
fifl of an oval placenta, and four fpoon-fhaped filaments or 
ftraps ^ to thefe laft the feeds immediately adhere. While 
thefe 
