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drotheca. It is: however completely closed outwardly. Also im 
A. coei (Pl. IV, fig. 23) a number of the corresponding projections 
contain a distinet inner cavity, but in most of them it seems to 
be completely filled by a chitinous secretion. 
According to the investigations contained in this 
paper I must maintain that the Campanulinidae have devel- 
oped from the Lafoézidae or partly from the Campanulariidae, 
and that the Sertulariidae must be derived from that 
group of the Campanulinidae in which the whole roof 
of the hydrotheca has been transformed into an oper - 
culum. 
Thujaria (Fleming) Lev. 
The aperture is vertical or obliquely ascending and provided 
with an abcauline sinus, in which is fixed. an opercular membrane, 
the distal part of which is a free valve. 
'The gonothecae of the species hitherto examined are smooth 
without transverse rings and without spines. 
In most biserial species the hydrothecae are almost symmet- 
rical, being only in a very slight degree turned towards the frontal 
face!) of the colony. 
Of this genus I have examined the following species: 
thuja (L.) Th. lonchitis (Ellis & So0l.), Th. articulata (Pall.), 
lichenastrum (Pall.), Th. annulata Krp., Th. carica Lev…. 
polycarpa Popp., Th. variabilis Markt., Th. cedrina (L.), 
cupressoides (Lepech.), Th. sinuosa Bale, Th. tuba (Bale), 
desmoides (Torr.), Th. hexodon (Bale), Th. juncea (Vanh.), 
Hartlaubi (Nutt.), TX. Hincksi (Mer.), Th. pinnata (Mer.), 
cylindrica (Clark.). 
sssgssgsg 
Sertularia (L.) Lev. 
Dynamena (Lamour.) 
The aperture is oblique and provided with two lateral teeth, 
between which there are found a deeper abcauline and a lower 
EF »Frontal« we call that face of the colony on which the gonothecae 
