HYDROIDA 



31 



Corymorpha nutans M. Sars. 



1835 Corymorpha nutans, M. Sars, Beskrivelser og Iagttagelser p. 7, PI. 1, Fig. 3. 



The hydrocaulus, when extended, attains a height of 100 mm. It is broad at the basis, attached 

 to the substratum by numerous rhizoids, and tapering upwards till it reaches its least breadth closely 

 below the polyp. The basis of the polyp is broad and surrounded by a proximal whorl consisting of 

 up to 50 tentacles, which, when extended, attain a length of 30 mm. The distal tentacles are small 

 and placed round the orifice in a main whorl composed of several irregular circles quite closely set. 



The gouophores are developed into free medusae with four radial canals, one well-developed 

 tentacle and three rudimentary ones. The gouophores are developed on 15 — 20 blastostyles, arising 



Zoom. __ „ _6oom. 1000 m. 2000m, 



Text-fig. G. The habitat of Corymorpha nutans in the Northern Atlantic. 

 (In the hatched regions the Htterature denotes a scattered, allthough common occurence). 



closely above the proximal whorl of tentacles. The blastostyles bear small alternating branches, each 

 provided with a large number of gouophores. 



Material : 



Iceland, 16 minutes N. W. Akraues, depth 26 — 30 fathoms (a couple of young polyps). 



The occurrence of the species is typically boreal. It is indigenous to the middle parts of the 

 littoral region. Towards the north it goes along the coast of Norway as far as L,ofoten and towards 

 the south it penetrates to the northern parts of France. The species is recorded by Jaderholm (1909) 

 from Matotschkin Schar (Nova Zembla) at the depth of between 2 and 5 fathoms. This find is most 

 peculiar and mysterious. Corymorpha nutans occurs not rarely in the North Sea, and I think Hart- 

 laub (1907) is right in supposing the specimen from the North Sea recorded by me (1905I as a Cory- 



