HYDROIDA 



of the Myriothclidae has developed, we cannot subscribe to the view of Kiihn (1913), reducing the two 

 families into one. The anatomical structure of the polyps of the two groups differs too much, and to 

 this difference must be attached a greater importance than the investigators have hitherto been inclined 

 to do; anatomically the difference between the groups is too great to allow their amalgamation, in 

 spite of the agreement of the two families as to the endodermal mucous gland portion near the ori- 

 fice of the polyp. 



Hitherto only one genus has been recorded of Myriothelidae. 



Gen. Myriothela M. Sars. 



''The large solitary polyps have only exceptionally slight indications of hydrocaulus ; in general 

 the base of the polyp is truncate or pointed and provided with rhizoids or filaments of adhesion, 

 which are in fact transformed tentacles. Both the ectoderm and the endoderm are stratified. The 

 tentacles are capitate and are irregularly distributed over the polyp and the blastostyles. The gono- 

 phores are developed on small polyp-like blastostyles attached to the inferior half of the polyp; the 

 blastostyles bear tentacles on their distal portion". 



The genus Myriothela is recorded from the northern seas and from the Antarctic Ocean. The 

 spread and rare occurrence of the individuals prevents us from deciding whether the genus is in fact 

 bipolar, as the finds hitherto recorded seem to indicate. 



Myriothela phrygia (Fabricius) M. Sars. 



1780 Lucernaria phrygia Fabricins, Fauna Groenlandica, Nr. 333, p. 343. 

 1851 Myriothela arctica M. Sars, Beretning om en zoologisk Reise, p. 134. 

 1873 phrygia G. O. Sars, Bidrag til Kundskab om Norges Hydroider, p. 130. 



"The capitate or almost cylindrical polyp extended reaches a length of about 400 mm. The 

 inferior termination of the polyp is truncate, and it is attached to the substratum by tentacle-like fila- 

 ments of adhesion. Above the portion wearing blastostyles it is studded with strong capitate tentacles; 

 on the other hand tentacles are wanting on the surface of the polyp between the blastostyles. 



The cryptomedusoid gouophores are developed on small polyp-like blastostyles, attached to the 

 inferior portion of the polyp and wearing capitate tentacles on their outward parts. The female blasto- 

 style has only one or two fully-developed gonophores at the same time, while the male blastostyles 

 wear numerous gonophores". 



Material : 



"Ingolf" St. 117. 6o.i3'N., 823' W., depth 1003 fathoms, -f- i C. 



St. 125. 68o8' N., i6o8' W., 729 -f- 0.8 C. 



Myriothela phrygia has an enormous faculty for extension and contraction, and it is likely to 

 share this faculty with its nearest relatives. A specimen I had the opportunity of observing when it 

 was brought up by the trawl in the Trondhjemfjord, had stretched its distal portion wearing tentacles 

 so strongly that the animal was as thin as a thread and measured up to 30 cm. in length; but as 



3* 



