fe Ep rol: ZQOOPMYVTES: 
By Sypney J. Hickson, M.A., F.R.S., Professor of Zoology in the Victoria 
University of Manchester ; and 
F. H. Gravety, BSc., Research Scholar in the Victoria University of Manchester. 
(4 plates.) 
THE collection of Hydroid zoophytes made by the ‘ Discovery’ Expedition proved 
to be remarkably rich and interesting. At the first inspection there seemed to be 
but few species, and these (with the exception of a few solitary forms of Lampra) 
were large, ramified and gorgonia-like in consistency ; but a careful examination of 
these large colonies soon revealed other species of epizoic habits which rapidly 
increased in numbers as our investigations proceeded. In the end the number of 
distinct species was twenty-five, or about twice as many as we expected to find. 
The large colonies of Haleciwm arboreum support Perigonimus antarcticus, 
Stylactis halecti, Campanularia everta, C. laevis, Campanulina, and Halecium 
tenellum. 
Perigonimus antareticus supports Campanulina A., Eudendrium insigne, and 
Lafoéina longitheca.  Eudendrium insigne was also found on a specimen of the 
Aleyonarian genus Ceratoisis, Sertularella plectilis and Campanulina B. are 
attached to a colony of Campanularia verticillata. 
Of the twenty-five species only two—Obelia geniculata from the Auckland 
Islands, and Dictyocladium fuscum from Coulman Island—were found outside the 
limits of McMurdo Bay and the edge of the great ice barrier. In other words, 
twenty-three of the twenty-five species represent the hydroid zoophyte fauna of 
the most southerly limit of our knowledge of marine zoology. Two species— 
Lampra microrhiza and Plumularia glacialis—were found only at the east end of 
the barrier. 
It seems probable that the part of McMurdo Bay from which these specimens 
came is covered with a continuous sheet of ice for the greater part of each year 
and in some years has no open water. There is good reason for believing that 
the great ice barrier is afloat, and consequently the few specimens obtained by the 
Expedition at the east end of the barrier may represent samples of a fauna that 
extends for some distance under the barrier towards the South Pole. 
We may regard this collection of Hydroid zoophytes as the representatives of 
a sub-glacial fauna, and subject to the condition that larve or free swimming 
VOL. III, 2 C 
