11 
THE VOYAGE OE H.M.S. CHALLENGER. 
I have endeavoured as much as possible to keep pace with the rapid additions of new 
species for which science has been indebted to various observers, amongst whom more 
particularly should be mentioned the Rev. T. Hincks, Mr. P. H. Macgillivray, Mr. J. B. 
Wilson, and Mr. Goldstein and others. But with the utmost desire to do full justice to 
priority of publication, numerous omissions will, I fear, be observed, in extenuation of 
which I can only plead either complete oversight or the circumstance that in many cases 
I have not found it possible to identify with certainty the species intended from the 
published figures and descriptions, in the absence of specimens. This remark applies 
more especially to certain more or less well-marked natural groups or families in which 
the common characters, so to speak, are so strongly marked as in some cases to mask the 
more minute specific features. Amongst these groups may be noticed more particularly 
the Reteporidse, Salicornariadae, Celleporidse, and Adeonese, amongst which, as well as in 
many other of the provisional or artificial escharan genera, are numerous forms which 
cannot be distinguished with certainty in the absence of the characters afforded by the 
chitinous parts. 
The number of species of Cheilostomata contained in the Challenger Collection, so far 
as I have been able to determine them, is about two hundred and eighty-six, of which, 
at the time when the collection came into my hands seven years ago, no less than one 
hundred and eighty appeared to be new, or were unrecognisable by me. 
Nor is this large proportion of new species much to be wondered at, seeing the peculiar 
conditions, especially as to depth of water and distance from land, under which the 
majority of the Challenger’s dredgings and trawlings were made. 
Though more or less visible throughout the greater part of the collection, the difference 
between a collection of Polyzoa made in deep water or at a distance from shore, and one 
made in the same geographical region near the shore, or in shallow water, is in no case so 
strongly exemplified as in that of the almost exclusively Australian genus Catenicella. 
On the voyage of H.M.S. “Rattlesnake,” employed in a surveying expedition on the 
coast of Australia and the neighbouring islands, the collections were of course chiefly 
made near the shore or in soundings of a moderate depth. On that expedition Mr. J. 
Macgillivray collected no less than seventeen or eighteen species of the genus, to which, 
either from Australia or New Zealand, about as many more have since been added, so that 
the number of known species of Catenicella living in comparatively shallow water may be 
roughly estimated at between thirty and forty ; all with two or three exceptions peculiar 
to the Australian region. 
Belonging to this genus the Challenger Collection contains eight species, seven of which 
only were procured in the Australian region at depths varying from 30 to 120 fathoms, 
and from closely contiguous Stations. An eighth, and the only new species, was 
obtained in the South Atlantic region off the coast of Brazil, where the depth is recorded 
as 350 fathums. 
