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DAVENPORT, — Urnatella gracilis, 
PLATE III. 
ABBREVIATIONS. 
an. Anus. mu. Muscle fibre. 
atr. Atrium. nph. Nephridium. 
clc. Cloaca. æ. Œsophagus. 
ol, ela, Closing cell of septum. pd. Stalk. 
cl. hp. Hepatic cells. Pl. Rectum. 
cta. Cuticula. spht. Sphincter between intestine 
di. sep.  Dissepiment. and rectum. 
ga. Stomach spht. atr. Atrial sphincter. 
gn. Ganglion. sul. atr. Atrial groove. 
in. Intestine. ta. Tentacle. 
kmp'drm. Kamptoderm. va. def. Vas deferens. 
loph. atr. Atrial ridge. 
Fig. 18. Median section of calyx of Urnatella. Camera drawing made from sev- 
eral adjacent sections. 405. 
19. Section through plane of line “Fig. 19” on Fig. 18. x 96. 
Figs. 20, 20°. Longitudinal and cross sections through chief nephriaium of calyx. 
x 610. 
21* 21^, 21°. Three sections taken across nephridium of one individual at 
different places, to show nature of the lumen and wall. Fig. 21* nearer 
the distal end of tubule. Fig. 21°, third section from mouth of tubule, 
at point of union of two nephridia into one. X 700. 
