HYDROIDA II 



91 



Norway; now the "Ingolf" has added two new localities, the one heing 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. 



600 



1000 m. 



Fig. XLIX. The occurrence of Cladocarpits 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 unbrauched 

 hydrocladia with several hydrothecce. All sarcothecse 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 reallv 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 



12* 



