THE DIGESTIVE ORGANS OF THE ALCYONARIA. 355 
movement through the tissues, yet we have no reason for 
believing that nerve cells retain this power when maturity is 
reached. Amceboid nerve cells and pseudopodial nerve fibres 
are unknown. We have no evidence that the Alcyonaria 
are more nervously sensitive than other lowly organised 
groups, so that it is impossible to regard this extremely well- 
developed system of amceboid cells with coalescing pseudo- 
podia as a specially differentiated ‘‘ nervous plexus.” 
1. Functions of the Mesoglcal Plexus.—tThe inges- 
tion of the inorganic particles of carmine by the endoderm 
cells is identical with the ingestion of organic food material. 
The distribution of ingested foreign matter by means of the 
wandering amceboid cells, usually most abundant about the 
digestive centres, is no doubt similar to the distribution of 
food material in a digested condition. I would, therefore, 
suggest that the distribution of nutriment is effected in the 
following manner :—Certain amceboid endoderm cells loaded 
with nutriment wander, or have wandered, into the mesoglea, 
where they form an amceboid plexus of cords and strands of 
cells which extends throughout the colony. The intimate 
connection between the digestive endoderm cells of the 
zooids and the plexus is maintained. If we suppose that 
throughout the plexus the nutritive protoplasm may be 
transferred from cell to cell—and the presence of carmine 
particles in the mesogloeal plexus affords substantial evi- 
dence for believing this to be the case—then this system of 
amoeboid cells must be regarded as a nutritive as well as a 
sensitive plexus, and by its means nutriment may be con- 
veyed from the digestive endoderm cells of the zooids to 
every portion of the colony. 
2. Excretory Function.—As the amceboid endoderm 
cells were observed to eject foreign bodies in the form of 
carmine particles (fig. 9, f. u.), it is very possible that the 
plexus has also an excretory function, the amceboid cells, 
which are to be regarded as the carriers of nutriment may 
also convey waste products to the ccelentera or lumen of the 
canals. 
