1897-98.1 Dr Masterman on Archimeric Segmentation. 309 
Metamere. 
Larval Bands. 
Nervous System. 
Archimeric 
Meta- 
mere. 
Metaccele. 
Metacoelic 
pore. 
Proto- 
troch. 
Meso- ■ 
troch. 
Meta- 
troch. 
Protomeric 
Part. 
Mesomeric 
Ganglion. 
Metameric 
Part. 
Heart. 
Trunk. 
Trunk 
cavities. 
? 
Nerves of 
proboscis. 
Collar 
nerve-gan- 
glion and 
post- oral 
ring. 
Dorsal and 
ventral 
chords. 
‘ Heart.’ 
Trunk. 
Trunk. 
Tail. 
Trunk 
cavities. 
Trunk 
cavity. 
Tail 
cavities. 
Gona- 
ducts. 
? 
Nephridia 
Yasa 
deferentia 
? 
Nerves of 
buccal 
shield. 
Nerves of 
epistome. 
Supra-oeso- 
phageal 
ganglion. 
Central 
nerve-gan- 
glion and 
post-oral 
ring. 
Central 
nerve-gan- 
glion, post- 
oral nerve- 
ring. 
Trunk -gan- 
glion and 
post-oral 
ring. 
Lateral 
and ventral 
chords. 
Lateral 
chords. 
Sub-neural 
sinus. 
3ody of 
adult. 
Body 
cavities. 
Gona- 
ducts. 
? 
Nerve- 
ring. 
P^adial 
chords. 
9 
Trunk. 
Trunk 
cavities. | 
Nephridia 
Supra-oeso- 
phageal 
ganglion. 
Sub-oeso- 
phageal 
ganglion 
and nerve- 
ring. 
Nerve- 
chords. 
(Heart.) 
Trunk. 
Trunk 
cavities. 
Nephridia 
Central 
nerve- 
ganglion. 
.. 
Trunk. 
Trunk 
cavities. 
? 
Pre-oral 
band of 
cilia. 
Post-oral 
band with 
tentacles. 
Peri-anal 
band. 
Apical 
plate pre- 
oral ring. 
Central 
nerve- 
ganglion 
post-oral 
ring. 
Dorsal and 
ventral 
chords. 
Sub-neural 
sinus. 
Caudal 
•egment. 
•• 
Pre-oral 
band of 
cilia. 
Mantle 
folds with 
setae. 
Trunk. 
Entero- 
cceles. 
Open into 
mesocoele. 
Pre-oral 
band of 
cilia. 
Post-oral 
band. 
Apical 
plate. 
Nerve-ring, 
post-oral. 
•• 
Trunk. 
Trunk 
cavities. 
? 
Pre-oral 
band. 
Post-oral 
band. 
Peri-anal 
band. 
Apical 
plate. 
Collar 
nerve- 
ganglion 
and ring. 
• * 
Trunk. 
Cavities 
of meso- 
blastic 
bands. 
Nephridia 
Pre-oral 
band. 
Post-oral 
band. 
Peri-anal 
band. 
Apical 
plate and 
nerve ring. 
Post-oral 
nerve-ring. 
Ventral 
chords. 
• • 
Trunk. 
Cavities 
of meso- 
blastic 
somites. 
Nephridia 
Br 
ain. 
Dorsal 
neuro- 
chord. 
Sinus of 
left aortic 
arch. 
Trunk. 
Cavities 1 
of meso- 
blastic 
bands. 
Nephridia 
Supra-ceso- 
phageal 
ganglion. 
Post-oral 
ring and 
sub-oeso- 
phageal 
ganglion. 
Ventral 
nerve- 
chords. 
Body. 
Ccelom. 
Nephridia 
(kidneys). 
• ® 
Fore-brain. 
Mid-brain. 
Hind-brain 
and neuro- 
chord. 
Trace in 
elasmo- 
branch 
embryo. 
