HYDROIDA II 



91 



Norway; now the "Ingolf" has added two new localities, the one being off the south-east point of 

 Iceland, the other in the eastern part of Danmark Strait, at a spot where several representatives of 

 the heat-loving deep-water fauna of the Atlantic have been found. The bathymetrical position of the 

 species is also somewhat doubtful: up to the present it has only been found in the middle and 

 lower parts of the littoral region. 



._ looo m. 



Fig. XL.IX. The occurrence of Cladocarpus bicuspis in the Northern Atlantic. 

 In the hatched region the literature notes a scattered occurrence. 



Gen. Thecocarpus Nutting. 



Upright colonies with branched or unbranched main stem, the apophyses bearing unbranched 

 hydrocladia with several hydrothecse. All sarcothecae immobile. The gonothecse are set in a corbula 

 formed by a metamorphosed hydrocladium; the blades of the corbula, or ribs, have each a hydrotheca 

 near its point of origin. 



Nutting (1900 p. 106) attaches primary importance to the question whether the stem is mono- 

 siphonic, a character which, even in distinction of species, is of subordinate weight; a species such as 

 Thecocarpus myriophyllum (Linne) occurs in northern seas not infrequently fertile with monosiphonic 

 stem, while other colonies have a polysiphonic basal part; but it is really only in southern waters 

 that strong colonies of this species are found with polysiphonic stems, at any rate a couple of feet 

 high. This feature, then, is of little or no interest from the point of view of generic distinction ; on 



