HYDROIDA 



37 



respect is the individual nr. 10 of the first table, the length of the blastostyles varying from 5 to 18 

 mm., and the thickness being inversely proportional to the length. The rest of the distinguishing 

 characters fall under what has been earlier stated. 



Corymorpha groenlandica is a typical form characteristic of the great deep of the cold area. It 

 proves to be widely distributed, from Spitzbergen to the Faroe Islands, and from Norway to Green- 

 land. It has also been recorded from Davis Strait. In the seas far to the north it rises to more shallow 

 waters. Thus it has been recorded near Spitzbergen at the depth of only 45 metres (Broch 1909). 

 A remarkable geographical exception is formed by the occurrence of the species in the deeper Atlantic 



20om. 6 oo n. ._ 1000 m. i 2000m. 



Text-fig. I. Localities of Corymorpha groenlandica in the Northern Atlantic. 



strata of the Trondhjem fjord. At present the occurrence of the species in this locality cannot be 

 accounted for. But a great deal may be said in favour of the notion that we have here in hand a 

 relict form, which has been able to accommodate itself to the altered circumstances in the same way 

 as Tubularia regalis Boeck and Stegopoma plicatile (M. Sars) which are rather frequently occurring 

 on or at the Lophohelia reefs of the fjord. 



Corymorpha sp. indet. 

 Indeterminable remnants of species of Corymorpha occur from the following localities: 

 "Ingolf" St. 28, 65°i4' N., 55°42' W., depth 420 fath., + 3°5 C, attached to the tube of a Pectinaria. 

 _ -124, 67°4o' - i5°4o' - - 495 - -ho°6- 



