JOURNAL OF MICROSCOPICAL SCIENCE. 
DESCRIPTION OF PLATE I, 
Illustrating Dr. P. M. Duncan’s paper on the Histology of the 
Reproductive Organs of the Ivid, Tigridia conchiflora ; with 
a description of the Phenomena of its Impregnation. 
Fig. 
1.—Transverse section of one ovarian cell, showing two ovules, one 
ready for impregnation (13-inch object-glass). @. External coat. 
&. Projection of the nucleus. c. ‘‘ The papillary structures,’ a por- 
tion of the placenta which is usually perforated by pollen-tubes, and 
~ with which the open micropyle is in contact when undisturbed by 
Q.—a. 
4.—a. 
manipulation. d. Position of the body of the nucleus, the embryo- 
sac being in its interior. e. Position of the micropyle when sepa- 
rated from the papillary structure near the placenta. (This portion 
of the placenta is continuous with the so-called conducting tissue of 
the style; the name placenta ought properly to be restricted to the 
tissue through which the vessels pass from the axis to the ovule). 
The ovarian wall is closely applied to the ovules in nature, but is 
readily separated by violence ; as growth proceeds after impregna- 
tion the wall becomes distant. 
Nucleus stripped of its external coat (4). d. Body; the unshaded 
central oval spot shows the square cells, and denotes the position of the 
internal pellucid embryo-sac. dw. Cells magnified (4). 0. Neck of 
the nucleus composed of elongated cells. c¢. Circular opening of 
the micropyle whose canal can be traced as a dark line extending 
upwards to the central light spot. ¢, «. Micropyle (mag. 4 object- 
glass). e. Part of immature embryo-sac, the position of its cells 
being shown by their nuclei (3). 
. Micropyle and “the papillary structure” slightly separated (4). 
ec. Overlapping circular cells of embro-sac (4). d. Some square 
cells from the upper part of embryo-sac (4). The ovule has reached 
its full devlopment before impregnation. 
Cells of external coat of ovule. 4. Cells of the projection of the 
nucleus. c. Micropyle in an ovule not fully developed. 
. Pollen-tube (cellular) from the stigma. 6. From thestyle. ¢. Drawn 
out from the “papillary structure” close to the micropyle; very 
turgid. d, e. Hair and cells of the conducting (nourishing tissue) 
tissue of the style (all + inch). 
