FILAMENTS OF THE CYNARES. 189 
(Fig. d.) The epidermis, again, is covered by a tolerably 
thick cuticle. Upon this cuticle rise peculiar, conical hairs, 
composed of two flat, contiguous cells, and 
whose gelatiniform, thickened membranes Fig. ¢, 
are also covered by the cuticle. (Fig. c.) 
When the interior cells of an irritable 
filament in the state of elongation are placed 
under a sufficient magnifying power and ac- 
curately defined, or are exposed by a longi- 
tudinal incision, they appear longitudinally 
striated, as if furnished with longitudinal 
fibres. (Fig. a.) 
But in the state of contraction their aspect 
is quite different, as is best seen in a fila- 
ment which has already become shortened 
below the summit of the corolla. At this 
time the filaments have lost their vitality, 
as is proved by the contracted condition of the primordial 
utricle. 
In this condition, if the air has been removed, all the cells 
present close, transverse strie, as if the thin filament were 
composed solely of spiral vessels. (Fig. 0). Those portions, 
consequently, of the filament in which more especially short 
cells exist exhibit the closest transverse striation, almost hke 
that of transversely striped muscle. 
This appearance is due to the circumstance that the cells in 
the act of shortening become very regularly and closely wrinkled. 
The walls of the cells, consequently, appear to be very closely 
and finely plaited, as many as from ten to twenty transverse 
wrinkles occurring in the space of =}, mm. ‘The apparent 
fibres which, as above said, run sometimes perpendicularly, 
sometimes obliquely to the 
longitudinal axis, correspond Fic. d. 
exactly to these transverse 2 ee 
wrinkles of the cell-wall. a ee = 
. The corrugation is seen in [ 
all the cells, including those ia. 
of the epidermis (figs. dand é), ee BI See 
= 
tt 
MOTT 
ONAHH WLS 
except that, as regards the re, 
innermost part, next to the 
alr-passages, the cells often remain un- Fie, ¢ 
wrinkled. RPP 
The corrugation of the cells, conse- a) : 
quent upon their shortening, may be 
observed to take place under the microscope, inasmuch 
as the water or glycerine entering the air-ducts kills 
