26 SYDNEY J. HICKSOX AND P. H. GRAVELY. 



length, and from 1'5-2'0 mm. in diameter at the mouth. The margin is armed with 

 15-20 blunt denticulations. The hydranths are large, but of the usual form in the 

 genus, and provided with about 30 tentacles 1 5 mm. in length. 



Gonosome. The mature gouotheca is 2 5 X 1*2 mm. in size, tall and cylindrical. 

 The proximal part of the gonotheca is slightly swollen, and the distal end almost 

 straight. It is supported by a short cumulated pedicel arising directly from the 

 hydrorhiza. 



The specimens attributed to Hartlaub's species differ from the type in one or two 

 particulars. The hydrothecse are not so fully expanded distally, the reduplications (?) 

 of the stem are not so well -marked, and the gonothecse are very different in shape 

 from those of the specimens from Calbuco.* But without further evidence as to the 

 sex and structure of the gouophores of this type we do not feel justified in creating a 

 special specific name for them. 



SUB-FAMILY HALECIINAE. 



The genera that are usually included in the sub-family llaledinae (Haled idae, 

 Hincks) are characterised by the rudimentary condition of the hydrothecse. The 

 tubular structures arising from the hydrocladia surround, like a collar, the base of the 

 hydrauths, but are quite insufficient to enclose and thereby afford protection to them 

 when retracted. 



It is, in our opinion, unfortunate that the term " hydrophore " has come into 

 general use for this rudimentary form of hydrotheca. There are many examples to be 

 found in the Ccdyptoblastea of hydro thecse that are not cup-shaped, such as the 

 cylindrical hydrothecae of Sertularella fornwsa and Syntheeiwn cylindricum (see 

 Nutting, 19.: p. 14), and it would be practically impossible to limit the use of the term 

 to hydrothecae that are tubular or cylindrical in shape. The use of the term hydro- 

 phore for those hydrothecse only which are not capable of receiving the retracted 

 hydranth would also be inconvenient. It is, therefore, the best course to adopt to 

 abandon the use^ of the term hydrophore altogether. 



The genus Halecium is usually regarded as distinguished from its allies Dlp- 

 locyatktu (Allman), Hydrodendron (Sars), and Ophivdes (Hincks) by the absence of 

 nematophores ; but one of us has observed the presence of nematophores on the 

 specimens of Halecium arboreum obtained by the 'Challenger' (3: p. 10, PI. IV., 

 figs. 1-3) and now in the British Museum, which were overlooked by Allmau, and the 

 specimens which we attribute to the same species have also nematophores. It does not 

 seem to us convenient to again split up the genus Halecium into groups containing 

 those which do and those which do not possess nematophores, but rather to add to the 

 characters of the genus, that " nematophores may or may not be present." As regards 

 the use of the term " nematophore," it is necessary to explain that we have adopted the 



* Oil the coast of Chili, approximately 41 S. by 71 W. 



