EXPLANATION OF PLATES. 
Abbreviations. 
a. atrium. 
aep'. epithelium of young atrium, 
c'. cavity lined with epithelium at 
position of old atrium. 
CO. common oviduct. 
ct. connective tissue stroma of 
ovary. 
ctn. nuclei of this stroma. 
ds. zone of formative cells in the 
dorsal region. 
ec. ectoderm, 
ec'. young ectoderm. 
ep. epithelium. 
g. gut. 
gl. gland cells. 
gp. genital pore. 
k. mitotic figure. 
Im. larval mouth. 
m. mouth. 
mf. muscle fiber. 
n. nuclei. 
ne. nerve. 
np. nuclei of the parenchyma 
proper. 
0 . ovary. 
od. oviduct. 
oy. cord of cells along line of 
future oviduct. 
p. penis. 
pa. parenchyma. 
ph. pharynx. 
ph’. young pharynx. 
phV. pharyngeal lumen. 
pi. penis lumen. 
ps. pharyngeal sheath. 
r. rhabdites. 
s. formative cells, (“ Stammzellen ” 
of Keller). 
t. testes. 
u. uterus. 
X). vacuole. 
va. vagina. 
vd. vas deferens. 
X. masses of cells found principally 
in dorsal region. 
y. yolk glands. 
yo. yolk within embryo. 
