HYDROIDA 



25 



Tubularia indivisa being globular, and accordingly broadly rounded in the distal part, while that of 

 Tubularia regalis is oval and showing an attempt to be pointed in the distal part. 



Tubularia indivisa has a very wide distribution. Its main occurrence in the boreal seas is bound 

 to the middle and deeper parts of the littoral region and to the upper part of the deep sea region. 

 From the cold area we find the species but once recorded, by Grieg (1914). After the examination 

 of his specimens I cannot confirm this record; the specimens consisting only of hydrocauli without 

 polyps, more probably belong to another species of Tubularia inhabiting the deep sea. 



To judge from literature, Tubularia indivisa penetrates rather far into the shallower parts of 

 the Arctic regions, where it is recorded even from the New Siberia Islands (Jaderholm 1908). How- 

 ever, as appears from what is stated above, there is a possibility that some of the Arctic individuals 



Text-fig. D. The distribution of Tubularia indivisa in the Northern Atlantic. 



are in fact to be referred to Tubularia regalis. — The species also penetrates far towards the south. 

 It is recorded by Fewkes (1881) even from the Caribbean Sea, by A 11 man (1877) from between Cuba 

 and Florida, and by Billard (1906) from the west coast of Africa. As Tubularia indivisa is recorded 

 at the same time both from the East and the West coast of North America, it must be characterized 

 as a circumpolar or rather "circumborear (Nordgaard 1912) species. 



Tubularia regalis Boeck. 

 i860 Tubularia regalis Boeck, Videnskabsselskabets Forhandlitiger for 1859. 

 1899 - T. variabilis Bonuevie, Norske Nordhavs-Expeditiou, p. 24. 



Colonies whose long, dark-brown-coloured hydrocauli are in the lower parts twisted together. 

 The stem is covered with a vigorous periderm, but shows no rings nor wrinkles. No collar is formed 



The Ingolf-Expedition. V. 6. 4 



