EEPOET ON THE HYDEOIDA. 
lix 
a depth of 450 fathoms, while all the others are comparatively shallow water species, 
their stations varying from 9 to 70 fathoms in depth. 
Desmoscyphus has yielded four species which, with the exception of Desmoscyphus 
gracilis from the "West Indian Region, have all been found in the South Atlantic. 
Two of these, however, Desmoscyphus pec tinatus and Desmoscyphus obliquus, afford an 
instance of unusually wide distribution, Desmoscyphus pectinatus having another station 
in the Australian Region, and Desmoscyphus obliquus also another in the East Indian. 
Synthecium, hitherto known only as a New Zealand genus, has yielded to the 
dredge of the Challenger two new species obtained off the south-west coast of Australia. 
Idia pristis, the only species as yet known of this remarkable genus, would seem to 
be widely distributed in the seas lying to the south of the equator. The Challenger 
obtained it from two stations, one in the South Atlantic Region and the other in the 
East Indian. In neither of these stations did the depth exceed 20 fathoms. 
The Plumularinae have yielded thirty-one species. As stated in the first part of this 
Report, it may be generally asserted of the Plumularinae that they have their greatest 
development in the warmer seas of both hemispheres, and that in tropical and sub- 
tropical regions they attain their maximum in multiplicity of forms, in the size of the 
colonies, and in individual profusion. 
Among the species of this group brought home few had been obtained from any con- 
siderable depth. Cladocarpus, however, which of all the genera of the Plumularinae 
would seem to be that which inhabits the greatest depth, is represented in the collection 
by two species, Cladocarpus pectiniferus, which was dredged from a depth of 900 fathoms 
in the Azoric Region, and Cladocarpus formosus, which was obtained by the trawl from 
a depth of 77 5 fathoms in the seas lying to the south of Japan. The depth of 900 fathoms 
from which Cladocarpus pectiniferus was dredged is the greatest depth from which any 
member of the Plumularinae has as yet been obtained ; Polyphm.aria pumila, Aglao- 
phenia flicula, and Aglaophenia acacia are also deep-water species, having been all 
dredged in the Azoric Region from a depth of 450 fathoms. Plumidaria insignis and 
Plumularia abietina were dredged oil’ Marion Island, in the Region of the Cape of Good 
Hope, from a depth of from 150 to 310 fathoms ; but none of the remaining species of 
the Plumularinae came from greater depths than 150 fathoms, most of them from depths 
under 100 fathoms, while many are quite littoral and came from depths ranging between 
8 and 20 fathoms. 
The discovery of Cladocarpus formosus in the Japanese Region is a fact of consider- 
able interest. This species had previously been obtained by the “ Porcupine” from the 
deep cold area which lies between Shetland and the Faeroe Islands, where it was dredged 
from a depth of 167 fathoms. Claclocarqms formosus thus affords an instance of the 
same species inhabiting two widely separated regions, with its absence, so far as we yet 
• know, from all intervening stations. 
