929 
A. W. WATERS—REPORT ON THE BRYOZOA. ZOO 
it occurs in the British and neighbouring seas, the Mediterranean and the 
Red Sea, and Australia, and though certainly elsewhere also, we must wait 
until more comparative studies of the ovicell have been made before we can 
be certain as to the distribution. There is below the aperture a small thin 
oval spot (fig. 11), clear in balsam preparations, which occurs in all specimens 
examined from various localities, but does not seem to have been mentioned, 
though a mark somewhat lateral is shown by Hincks. I do not find this mark 
in any other species nor in Crisia denticulata, var. gracilis, Busk, which, 
however, I should not place with denticulata. 
The ovicell is lateral, short, and pomiform, as I would call such ovicells, in 
opposition to the pyriform ovicells. In two or three eases there is a narrow 
tube from the distal base of the ovicell. 
The distance from zocecium to zocecium is about 0°28 mm. Without the 
ovicells the determination of Crisia is most difficult and often with small 
pieces impossible. 
However, another character of great importance is the distance apart of 
the zocecia, and if mature portions are taken and not the extremities it will 
be found that most correspond very nearly to type measurements. For such 
measurements I set the threads of a micrometer over a typical portion and 
then bring a number of others under the micrometer. Harmer has shown 
that the position of the basis rami may be of use in some species, but the 
number of cases in which it will be of use is somewhat restricted. The 
position depends to a large extent upon the width of the opening for the 
joint, and it is worth attention that the size of the main and lateral joints 
seems in all cases to be the same, and when they are very large then the 
opening is directed laterally and is usually about halfway between the twe 
zocecia. The size of the aperture of the zocecia is certainly a character of 
primary importance and there is but very slight variation through a colony. 
The mode of branching is often a character of considerable value. The 
position of the joint has been stated in two ways, either counting all the zowcia 
of an internode below the new branch, or only the zocecia on the one side, as, 
for example, the fifth zocecium of an internode is the third on the side from 
which the new branch commences. Harmer in his important paper on Crisia 
speaks of the number on the one side, and I shall therefore rollow him, though 
perhaps it would have been better to give the total number of zocecia before 
the commencement of a branch. 
In the C. tubulosa group the zocecia are far apart (about 0°5—-0-6 mm.), the 
aperture of the zocecia is large (about 0-1 mm.), the oviceli is central, pyriform, 
and long. In C. ramosa, Harm., the distance is about 0:4 mm. apart, with the 
aperture about 0°07 mm. In the C. denticulata group the distance is about 
0-3 mm., the aperture about 0°06 mm., the ovicells are shorter and more to one 
side than in the truly pyriform ovicells. 
We are acquainted with radicles in various positions, but one from Khor 
