BRYOZOA FROM AUSTRALIA. 677 
Filisparse*, &c.; and further, I find that the size (0-008 millim.) 
of these pores varies but very little, having preparations of recent, 
Tertiary, Cretaceous, and even Paleozoic forms of many genera 
showing scarcely any variation in this respect. This structure is well 
shown in sections figured by J. Beissel, especially in pl. x. fig. 127, 
in his paper ‘“‘ Ueber die Bry. der Aachener Kreide,” Nat. Verh. Holl. 
Maat. Weten. Haarlem, xxii° Deel—a most valuable work, which does 
not seem to have received the attention it deserves. These, I take it, 
are the homologues of the much larger pores in the front of nearly 
all Chilostomata, which there also cause the zocecial ornamentation. 
Besides these, there are in the interior of the Cyclostomatous tube 
much larger pores, and these I have found to occur with a certain 
amount of regularity, and approximately at certain distances apart ; 
so that when a zocecial tube is cut open correctly along its axis, 
one or two rows of these pores are seen, and the position of the 
rows and the distance apart of these interzocecial pores seem to be 
of specific importance. Having noticed this much, it 1s not un- 
natural to consider these pores the homologues of the rosette-plates 
of the Chilostomata, and upon more careful examination we find 
support for this view. This can best be studied where the pores are 
long, as, for instance, in Heteropora pelliculata +, Waters, in which a 
diaphragm or plate, seemingly perforated in the centre, occurs in 
the middle of the pore-tube (see Plate XXXL. fig. 24): and thus it 
seems entirely to correspond to the simplest of the rosette-plates 
among the Chilostomata. 
As already indicated, probably the typical distance and the order 
of these pores will in most cases be distinguishable ; yet there is not 
an absolute regularity, and it must be remembered that in the 
Chilostomata when the number of rosette-plates increases so does 
the irregularity ; when there are four or six lateral plates it is by 
no means uncommon to find that one of these is replaced by two 
smaller ones ; but then upon examining the walls of two or three 
cells the type can be made out. 
In such genera as Entalophora &c. there are always the fine 
surface-pores {, although sometimes from the state of preservation 
or fossilization this is not apparent, and a great number have been 
incorrectly described as without this structure ; but in some genera, 
such as Hornera, some Idmonew, such as Idmonea radians, and a 
number of others both living and fossil, there are, over part of the 
* There are also such pores on the dorsal surface of Lichenopora; and as 
this dorsal surface is attached to stones, &., it is in such eases difficult to 
understand their use. 
t There is no doubt at all that H. neo-zelanica, Busk, is only a synonym for 
H. pelliculata. 'The New-Zealand specimens, for which I am indebted to Prof. 
H. A. Nicholson, had evidently been dead some time, and the exterior was slightly 
stained and corroded; but the interior was well preserved, and the internal 
characters are identical in these and the Japan specimens; and the difference 
in the shape of growth is not greater than in the series of Japanese specimens 
in the British Museum. 
t In recent Jdmonea Milneana, these “dots” are raised; but here also they 
are perforated, as pointed out by Mr. S. O. Ridley, so that this only indicates 
an elongation of the pore-tube. 
Q.J.G.8. No. 160. 22 
