130 
The reproduction and increase takes place by means of 
budding and of eggs. The egg developes into a ciliated 
larva, which undergoes a change that has been compared by 
Joliet* to that taking place in the developed polypide, so 
that the young polypide buds in the larva, which thus 
represents the zooecium. This zooecium now diyides into 
two in somewhat different ways in various species, and the 
growth of the colony proceeds by division of the growing 
zocecia. We may, however, examine a little further 
as representative, the growth of a Flustra or Eschara, as 
worked out by Nitsche in Flustra membranacea. The cells 
or zooecia become long, almost tubular, and after the poly- 
pide has begun to bud in the lower part a division takes 
place across from the lateral walls, thus dividing the lower 
part off into a rectangular cell the usual shape and size. 
In this way the Flustra increases in length, and the increase 
in breadth is brought about by the division of these terminal 
zooecia in the direction of their longer axes. 
The budding of the polypide inside the cell has been 
followed out by several observers, as Nitsche, Claparede 
Smitt, &c.; and a reference to their figures will explain 
more than pages of description. The bud, which at first is 
only a cellular protuberance, soon shows divisions which 
represent the tentacles, and ultimately these become 
separated tentacles, the canal of the polypide becomes fully 
developed, the oral aperture is now formed in the zoo- 
ecium, and the now completed polypide cam extrude itself 
through this opening, and the cilia on the tentacles create 
currents which bring a supply of food to the mouth of the 
polypide. After a time, it shows symptoms of loss of 
vitality, and then in a very short time the polypide has 
passed through a gradual diminution until it has dis- 
appeared, leaving only a small, dark body, enclosed in a 
thin membrane, and the zooecium is now empty, excepting 
# “Bryozaires des cotes de France,” par M. Lucien Joliet. 
Lacaze-Duthiers, Archives de Zoologie Experimental, 1877, pt, 2. 
