776 
ROBERT PAYNE BIGELOW 
EXPLANATION OF FIGURES 
All figures are camera drawings, except as otherwise noted below. They were 
made at the magnification indicated and reduced in reproduction to about one- 
third the original size. ^ 
LETTERING COMMON TO ALL THE FIGURES 
b. 
Battery of nettle cells. 
P- 
Lateral pocket lined with pitted 
c. 
Concretions, or otoliths. 
epithelium. 
ec. 
Ectoderm. 
p.e. 
Pitted epithelium. 
en. 
Endoderm. 
r. 
Rhopalium. 
Q- 
Ganglion cell. 
r.c. 
Rhopalial canal. 
h. 
Hood. 
)\r. 
Rhopalial ridge. 
m. 
Muscle fibers. 
s.e. 
Sensory epithelium. 
m.l. 
Marginal lappet. 
s.g. 
Dorsal sensory groove. 
m.p. 
Marginal endodermal pocket. 
s.n. 
Sensory niche. 
n. 
Layer of nerve fibers. 
Figs. 1-12, 21-34, Chrysaora; 13-16, Pelagia; 17-20 and 35-38, Dactylometra. 
1 View of the sensory niche of a Chrysaora as seen from the under side by trans- 
mitted light. The specimen from which this was taken was a young one 25 mm. in 
diameter with 24 tentacles. X 200. 
2 Portion of the margin of the umbrella of a full grown Chrysaora containing 
the rhopalium and adjacent organs. The cut surfaces are in tangential and radial 
planes. X 56. This figure is a reconstruction from sections. 
3-9 Diagrams from typical sections of the series used in the construction of fig. 
2. X 56. Fig. 3 corresponds to plane I in fig. 10, fig. 4 to II, fig. 5 to III, fig. 6 
to IV, fig. 7 to VI, fig. 8 to VII, and fig. 9 to VIII. 
