OVICELLS Of Cl'CLOSTOMATOUS BEYOZOA. 
275 
On some Ovicells of Cyclostomatous Bryozoa. 
By Arthur Vm. Waters, F.L.S., F.G.S. 
[Read 5th April, 1888.] 
(Plate XIV.) 
For the determination of the Cyclostomatous Bryozoa the ovi- 
cells are certainly most important characters, and in many cases 
are undoubtedly of generic value ; hut how far this is universally 
the case we are not yet in a position to decide. It may, how- 
ever, safely be said that the Cyelostomata will never be rescued 
from their present confusion until we are more fully acquainted 
with these receptacles. Though of such paramount importance, 
they are not known in a large majority of species. This is partly 
on account of insufficient search, but more from the fact that 
large numbers of specimens are often found without any ovi- 
cells ; so that in some common species they are as yet unknown. 
For instance, Hornera concatennata , Beuss, a fossil found abun- 
dantly in the Miocene of Italy, Germany, Austria, and Hungary, 
has, so far as we know, never furnished an ovieell. 
It will thus be seen that with the Cyclostomata it is often the 
case that abundant material is necessary for true appreciation of 
the characters, and therefore it was a considerable disappoint- 
ment that the results of the £ Challenger ’ Expedition were not 
richer in this respect. I am, however, now able to add figures of 
the ovicells of three species found by the ‘ Challenger,’ one from 
‘ Challenger’ material, and two from specimens in my own collec- 
tion from other localities. 
Hornera eissurata, Busk. (Pl. XIV. figs. 1, 3, 4, 7.) 
Taking them in order: when, through the kindness of Mr. John 
Murray, I received two colonies oi“Idmonea jissurata," Busk, from 
‘ Challenger’ “Station 320,” near Monte Video, I was surprised 
to find a dorsal ovieell upon one, giving sufficient ground for 
removing it to Hornera-, but the structure of both the front and 
back would have led me to do this independently of the ovieell. 
As Miss Busk had kindly sorted and forwarded the specimens, 
I informed her what I had found ;• and she replied that she had 
also noticed them, and mounted some for the British Museum, 
and added that it was to be regretted that “ there did not happen 
to be any among the rather numerous specimens selected for 
LINN. JOURN. ZOOLOGY, VOL. XX. 22 
