306 BE. A. MINCHIN. 
monaxons have their long axis parallel to the canal, in the 
wall of which they lie (l.c., p. 297), and are placed “in a 
meridian of the direction of the current” (l.c., p. 298). A 
glance at any Leucosolenia is sufficient to dispel this 
illusion; in all parts of the sponge the monaxons are found 
pointing in every possible direction (compare Fig. 108, Pl. 21); 
only at the oscular rim is a slight tendency to regularity 
noticeable. 
The first sign of the formation of a monaxon spicule is the 
division of the nucleus of a dermal epithelial cell, followed 
by incomplete division of the cell-body (fig. 1—38, 41, 73— 
75). This division of the mother-cell, as it may be termed, 
marks out the two formative cells, which are not, as a rule, 
completely separated from one another in early stages, but 
later become distinct and largely independent of one another. 
A further point to note is that the formative cells retain a 
connection with the dermal epithelium from which they are 
derived (figs. 43—48; especially fig. 45). This point is of 
importance, since Woodland (1907) has based theoretical 
deductions upon the assumption that the scleroblasts have 
“ Jost connection with the rest of the organism”? (l.c., p. 60). 
He even speaks of the scleroblasts as “ 
meaning thereby, as I understand him, not that they belong 
to the class of amcebocytes (i.e. archzeocytes), but that they 
are completely independent of other histocytes. It is always 
more easy to overlook than to discover connections between 
cells, and, therefore, positive observations are of more value 
than negative ones in their bearing on‘questions of this 
kind; but, in any case, I should doubt if scleroblasts, or 
skeletal tissue generally, could be supposed to be more 
independent than any other class of tissue-cells, and I 
consider the term wandering cells misleading as applied to 
the scleroblasts, and likely to produce a mistaken theoretical 
bias.? : 
wandering cells,” 
1 Woodland admits a connection between the scleroblasts and the dermal 
epithelium in some cases (1905, p. 243, and PI. 15, figs. 45—49), but con- 
siders that in other cases no such connection is retained (l.c., fig. 48). 
