128
continue to use “hyperstomial” or “prominent” (introduced
by Hincks 1880 ) to defi ne any ovicell whose roof is well
above the colony surface (see Fig. 1 in Introduction, Figs. 2.1 ,
2.3 , 2.5 , 2.6a (A–C), b (C, D, F), 2.7a (A–C), and 2.8A–E ).
The limits of the ovicell opening (mostly between the upper
edge of the calcifi ed transverse wall of the zooid and the
lower edge of the ovicell roof) relative to the zooidal orifi ce
(not always refl ected in the skeleton) are often diffi cult to
recognize without studying internal structure. In this regard,
the terminology of Jullien ( 1888 ) is of dubious value. This
also concerns the term “hypostomial,” provisionally introduced by Ryland ( 1968 ).
The terms “erect” and “recumbent” (Busk 1884 ), and
“dependent” and “independent” (Levinsen 1909 ), should be
Fig. 2.7 ( a ) Schematic diagrams of the position of the brood cavity
relative to the colony surface. A– C , hyperstomial (prominent) ovicells
( A , Bugula neritina ; B , Notoplites tenuis , Tricellaria gracilis ;
C , Corbulella maderensis ). D , E , peristomial ovicells ( D , Margaretta
barbata ; E , Cylindroporella tubulosa ). F , G , I , subimmersed ovicells
( F , Valdemunitella lata – each lobe of bilobate ooecium communicates
with visceral coelom via separate pore; G , Porella smitti – ectoooecium
covered with secondary calcifi cation; I , Puellina radiata – each lobe
of bilobate ooecium communicates with visceral coelom via separate
slit or pore). H , endozooidal ovicell ( Selenariopsis gabrieli ). In A – C
and F – I the ooecial coelom communicates with the ooecium-producing distal zooid via a communication slit or pore(s), often plugged by
non-specialized epithelial cells (not shown). In D and E the ooecial
coelom is confl uent with the hypostegal coelom of the ooecium-producing distal zooid. In A , B and G ovicells are acleithral, in C , F and
H cleithral, and in I semicleithral. Calcifi ed walls and zooidal opercula
are shown in black and by hatching, membranous walls (including
pseudopores) in red. ( b ) Schematic diagrams of the position of
the brood cavity relative to the colony surface. A , endozooidal
ovicell ( Chartella membranaceotruncata ). B , immersed ovicell
( Crassimarginatella sp.). C , internal brood sac with rudimentary ooecium ( Cauloramphus spinifer ). D , E , internal brood sacs ( D , Cryptosula
pallasiana ; E , Watersipora subtorquata ). F , endotoichal ovicell
( Cellaria tenuirostris ). In A and B the ooecial coelom communicates
with the ooecium-producing distal zooid via a communication slit
or pore(s), sometimes plugged by non-specialized epithelial cells
(not shown). In C the coelom of the kenozooidal ooecium communicates with the maternal zooid via a septular communication pore(s)
plugged by a pore-cell complex (not shown). In D the internal brood
sac communicates with the vestibulum of the fertile zooid. In E the
internal brood sac opens to the environment independently of the
vestibulum. In A ovicell is acleithral, in B cleithral. Calcifi ed walls and
zooidal opercula are shown in black , membranous walls (including
pseudopores) in red
2 Cheilostome Brood Chambers: Structure, Formation, Evolution
continue to use “hyperstomial” or “prominent” (introduced
by Hincks 1880 ) to defi ne any ovicell whose roof is well
above the colony surface (see Fig. 1 in Introduction, Figs. 2.1 ,
2.3 , 2.5 , 2.6a (A–C), b (C, D, F), 2.7a (A–C), and 2.8A–E ).
The limits of the ovicell opening (mostly between the upper
edge of the calcifi ed transverse wall of the zooid and the
lower edge of the ovicell roof) relative to the zooidal orifi ce
(not always refl ected in the skeleton) are often diffi cult to
recognize without studying internal structure. In this regard,
the terminology of Jullien ( 1888 ) is of dubious value. This
also concerns the term “hypostomial,” provisionally introduced by Ryland ( 1968 ).
The terms “erect” and “recumbent” (Busk 1884 ), and
“dependent” and “independent” (Levinsen 1909 ), should be
Fig. 2.7 ( a ) Schematic diagrams of the position of the brood cavity
relative to the colony surface. A– C , hyperstomial (prominent) ovicells
( A , Bugula neritina ; B , Notoplites tenuis , Tricellaria gracilis ;
C , Corbulella maderensis ). D , E , peristomial ovicells ( D , Margaretta
barbata ; E , Cylindroporella tubulosa ). F , G , I , subimmersed ovicells
( F , Valdemunitella lata – each lobe of bilobate ooecium communicates
with visceral coelom via separate pore; G , Porella smitti – ectoooecium
covered with secondary calcifi cation; I , Puellina radiata – each lobe
of bilobate ooecium communicates with visceral coelom via separate
slit or pore). H , endozooidal ovicell ( Selenariopsis gabrieli ). In A – C
and F – I the ooecial coelom communicates with the ooecium-producing distal zooid via a communication slit or pore(s), often plugged by
non-specialized epithelial cells (not shown). In D and E the ooecial
coelom is confl uent with the hypostegal coelom of the ooecium-producing distal zooid. In A , B and G ovicells are acleithral, in C , F and
H cleithral, and in I semicleithral. Calcifi ed walls and zooidal opercula
are shown in black and by hatching, membranous walls (including
pseudopores) in red. ( b ) Schematic diagrams of the position of
the brood cavity relative to the colony surface. A , endozooidal
ovicell ( Chartella membranaceotruncata ). B , immersed ovicell
( Crassimarginatella sp.). C , internal brood sac with rudimentary ooecium ( Cauloramphus spinifer ). D , E , internal brood sacs ( D , Cryptosula
pallasiana ; E , Watersipora subtorquata ). F , endotoichal ovicell
( Cellaria tenuirostris ). In A and B the ooecial coelom communicates
with the ooecium-producing distal zooid via a communication slit
or pore(s), sometimes plugged by non-specialized epithelial cells
(not shown). In C the coelom of the kenozooidal ooecium communicates with the maternal zooid via a septular communication pore(s)
plugged by a pore-cell complex (not shown). In D the internal brood
sac communicates with the vestibulum of the fertile zooid. In E the
internal brood sac opens to the environment independently of the
vestibulum. In A ovicell is acleithral, in B cleithral. Calcifi ed walls and
zooidal opercula are shown in black , membranous walls (including
pseudopores) in red
2 Cheilostome Brood Chambers: Structure, Formation, Evolution