158 
But even these latter zocecia are not the outermost compo- 
- nents of the colony; from the anterior wall of each of them 
originates a long slender flattened tube of the same breadth, 
but two or three times as long as a normal cell. These tubes 
are surrounded by a very delicate chitinous membrane, and 
lined with a layer of prismatic cells. Smith having in some 
cases overlooked the longitudinal septa between the different 
tubes, believes this zone to form at first an undivided flat- 
tened expansion surrounded by a membrane, and filled with 
** adipose corpuscula”’ (so he calls, in this case, the prismatic 
cells which secrete the endocyst) ; but this is, I think, a mis- 
take, and the appearance of an undivided margin is caused 
only by the fact that the chitinots membrane is very trans- 
parent, and the single tubes are in very close juxtaposition. 
The examination of specimens preserved in spirit and 
especially transverse sections made from this part of the 
colony, show very clearly that the longitudinal septa are 
always present from the beginning. The marginal zone of 
Flustra membranacea is, therefore, not to be regarded as a 
**common bud” of the whole colony, but as an aggregation 
of many “‘ common buds” produced by single zoccia, every 
tube being really a ‘‘ common bud” in the way I should like 
this name to be understood. Indeed, every tube is equiva- 
lent to two or three zocecia, into which it is afterwards divided 
by secondary transversal septa. 
The most curious and interesting mode of evolution Smitt 
attributes to the Bryozoa, is the so-called reproduction by 
** groddkapslar,” 7. e. “germ capsules.” Every one who 
has studied the anatomy of marine Bryozoa is well acquainted 
with the fact that only a very small part of the little cells of 
which every colony consists contains completely developed 
polypides; whilst the younger cells at the edges of the colonies 
enclose immature buds, the eldest cells are either quite desti- 
tute of polypides and contain nothing only circular or oval, 
sometimes also irregularly-shaped brown bodies or these said 
bodies together with a new budding polypide. Only the 
intermediate cells between the youngest and the eldest show 
completely developed polypides. ‘These brown bodies, lying 
in the interior of the cells of this part of the colony, which 
was formerly believed to be in a state of decay from want of 
polypides, have been mistaken very often for true ova. 
Smitt having witnessed many times the true ova of different 
species, rejects wholly this opinion, and states quite correctly 
that these brown bodies are products of the decomposition of 
the polypide formerly lodged in the cell; but the fact that 
they are often found associated together with a new bud of a 
