HYDROIDA II 



73 



of the h\-drotheca. All the sarcothecse are adcaulinally split, and have a slightly dentate margin. The 

 hydrotheca is broad, and has a very slighth' curved opening margin; its basal part has a somewhat 

 thicker wall than the distal two-thirds, and the boundary between the two portions is apparent as a 

 fine line abcladiallv directed obliquely forward towards the opening; hydrothecal ribs or septa lacking. 

 The internodium shows two to four inner ribs at the adcladial side of the hydrotheca; one such, which 

 is three-branched, and markedly prominent, forms a boundary between the proximal sarcotheca and 

 the internodium. 



The gonothecae are situate on the stem at the apoplnses. The young gouotheca shows distalK 

 a peculiar oblique termination, the one side of which gradually projects further forward, suggesting 

 that the fully developed gouotheca would be furnished with a roof-like upper lip. Phylactogonia 

 lacking. 



66°33' N., 20°05' W., depth 44 fathoms, 5,6° 



Material : 



"Ingolf St. 127 



Iceland: Tistil fjord, 66°43' N., i4°53' W., — 78 - 



Ritchie (1912 p. 226) refers this species to Cladocarpus, but with a query, as he did not find 

 gonangia in his specimens. These agree entirely with the present colonies (fig. XXXVI) which, from 

 the comparatively short, broad hydrotheca;, can hardly be 

 confused with other species from northern waters. The col- 

 onies in question show that the species should be placed 

 under Halkonian'a. The gonangia occur in several stages of 

 development, but none fulh- developed. The series of phases 

 represented in the colonies investigated are entireh' parallel 

 to what we find in Cladocarptis integer ( G. O. Sars); the 

 oldest stage also seems to show that it developes, as does 

 the species mentioned, an "upper lip" which will dome out 



Fig XXXVI. Halico7-naria campaniilata from "In- 



more or less over the opening; further investigations must g^'^,. gj_ j,. Hydrothecate internodium from a 

 determine, how far the development proceeds. hydrocladium in side and front view, (x 601. 



Phslactogonia are altogether lacking in the colonies here concerned, and the species must 

 consequently be regarded as a HaUcoriiaria; there is, however, the possibility that it ma\ later prove 

 to be a primitive Cladocarpus. The otherwise close resemblance of the species to Cladocarpus integer 

 would also seem to point in the same direction; the last-named species has hitherto likewise been 

 regarded as a Halicornaria, but, as is further explained below, it is as a matter of fact a primitive 

 Cladocarpus, whose phylactogonia do not always or everywhere attain development. We cannot 

 therefore altogether disregard the possibility that Halicoriiaria campanulata may also under normal 

 conditions develope more or less regularly occurring phylactogonia. But as long as this has not been 

 shown to be the case, the species must remain in the genus Halicornaria. 



Ritchie (1912 p. 227) could not state the locality of origin of the .species nearer than "from 

 the neighbourhood of Iceland", which from a bio-geograplucal point of view is very meagre inform- 

 ation indeed. The localities now recorded are the more surprising, since we should a prion suppose 



The Ingolt-lixpcdition. \. 7. 



