HYDROIDA II 



35 



Creeping colonies with tubular hydrotheca:. The hydrotheca stalk is irregularly, but distinctly 

 ringed or spirally coiled. The hydrothecie pass over evenh- into the stalk, they are somewhat 

 expanded at the base, then tapering slightly upwards, to expand again a little towards the open- 

 ing margin, which curves somewhat outwards. The opening margin itself has four low, but distinctly 

 discernible teeth, and has four triangular opercular plates fastened between them. 



The gonothecce are unknown. 



Material : 



Greenland: Egedesminde, depth 30-50 fathoms. 



Scattered specimens of this high-arctic species have been found at West Greenland, Spitzbergen, 

 in the Rlurman Sea, the Barents Sea, the White Sea, the vSiberian frozen Sea and the Sea of Okhotsk, 

 and must thus doubtless be referred to the circumpolar species. It belongs to the middle parts of the 

 littoral region. 



Family series Haleciina nov. 

 Family Haieciidae. 



The hvdrothecse are radially symmetrical and very small, at times practicalh' altogether dis- 

 appearing; the_\- have as a rule a basal cavity, often marked off from the h\-drotheca itself by a dia- 

 phragm. The hvdranths are large, and cannot be drawn quite into the hydrothecce. They have a 

 conical proboscis, and their gastral endoderm falls into two divisions, answering to the fore-stomach 

 and stomach of the polyp, which as a rule are separated by a limit indicated by a more or less marked 

 ring furrow round the body of the polyp. The basal part, the stomach, forms the digestive portion. 

 The polyps are radially symmetrical in structure. The colonies are stolonial or sympodial, with simi)le 

 or derived growth of the tips. 



Gen. Halecium Oken. 



Creeping stolonial, or upright s>-mpodial colonies with small radially symmetrical hydrothecse 

 with basal cavity. The diaphragm can be present or lacking. Nematothecte and nematophores lacking. 

 The gonophores are developed in gonothecce. 



The Halcciufu colony, in species with polysiphonic stem, often presents a peculiar appearance, 

 differing greatly from that of other hydroid colonies, as the polysiphonic main stem, which is gener- 

 alh- very strongly developed, most frequentl}- presents the same impression as an altogether irregularly 

 branched rhizocaulome, while the outer parts of the branches almost always exhibit regular ramifica- 

 tion. Haleciioii viiuutiini Broch especially, seems in some respects to take up a remarkable and 

 exceptional position; according to Kramp's observations (1913 p. 5) it can at times exhibit large colon- 

 ies of composite structure with rhizocaulome-like polysiphonic main stem and main branches, while 

 otherwise, the species normall)- presents small, monosiphonic colonies proceeding from a network of 



