152 
THE VOYAGE OE H.M.S. CHALLENGER. 
POLTCLINID^. 
Branchiai sac with 
wide meshes. 
I 
Pharyngodictyon. 
Branchial sac normal. 
Branchial sac not 
papillated. 
Branchial sac with papillae 
projecting from the interior. 
Sand-grains imbedded in 
and incrusting test. 
I 
Psammaplidium. 
Test not incrusted 
with Sand. 
Tyldbranchion. 
Intestinal loop simple. 
Stomach-wall thickened. 
Intestinal loop 
twisted. Stomach- 
wall smooth. 
I 
Atrial aperture 
on the 
anterior end. 
Atrial aperture 
on the 
dorsal surface. 
I 
Aplidium. 
Systems 
simple. 
I 
Polyclinum. 
Systems 
compound. 
Aurantium. 
Branchial aperture with 
more than six lobes. 
Branchial aperture 
six-lohed. 
Wall of stomach 
folded. 
Wall of stomach 
areolated. 
Wall of stomach 
folded. 
Wall of stomach 
areolated. 
Systems Systems Post -abdomen Post-abdomen 
simple. compound, separated from not separated 
f I abdomen by from abdomen 
Circinalium. Fragarium. constriction. by constriction. 
Wall of 
stomach 
folded 
transversely. 
Parascidia. Morchellioides. Atopogaster. 
Wail of Post- 
stomach abdomen not 
folded separated 
longitudinally. from 
abdomen by 
constriction. 
Post-abdomen 
separated from 
abdomen by 
constriction. 
Sidnyum. 
I 
Systems Systems 
simj)le. compound. 
Syrwieum. Morchellium. 
Post-abdomen 
separated 
from abdomen 
by constriction. 
I 
Polydinoides. 
Post-abdomen 
not separated 
from abdomen by 
constriction. 
I 
Atrial aperture 
provided with 
a languet. 
Amaroucium. 
Atrial aperture 
six-lobed. 
I 
Sigillina. 
Pharyngodictyon^ n. gen. 
Colony club-shaped, or consisting of a “ head ” placed on a short peduncle. 
Systems inconspicuous. 
Ascidiozooids very long antero-posteriorly, and distinctly divided into regions. 
Test of a firm gelatinous consistence. 
^ From <f>xQvy^ and S/*t5ov. 
