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are smaller in the specimens illustrated by fig. 1 on plate 9, and by fig. 3 
on plate 8. 
The digestive system is best shown in figs. 2 and 3 on plate 12, and 
it is from these figures that the digestive system in the accompanying 
figure has been taken. The loops within the spiral made by the digestive 
tube shown in fig. 3 on plate 8 I interpret as a portion of the mesentery 
attaching the alimentary canal to the dorsal body wall. 
Eldonia ludwigi Walcott, viewed from the ventral side. 
The marginal brim, in its details and in its relation to the rest of 
the animal, is best represented in fig. 3 on plate 12, and the proportions 
of the brim as figured are taken from this illustration. 
The central ring and the radiating water tubes are best shown in 
figs. 1, 2 and 5 on plate 9. In fig. 1 the gradual expansion of the tubes 
toward the marginal brim is well brought out (on tho right hand side). 
In the restoration the size of the central ring is slightly exaggerated in 
order the better to bring out its relationships to the other structures. 
Muscle fibers are only evident in the specimen from which fig. 5 on 
plate 9 was taken. The diffuse appearance and the width of this muscle 
e Pi ee 
AO PRATO Rie 
Los db 
