HYDROIDA II 



99 



Iceland: Vestmano, depth 25 fathoms 



10 miles W. of Akranes (depth not stated) [labelled Scrtularclla polyzonias\ 

 Bredebugt, depth 7-12 fathoms 



6 5 oo' N, 2 4 3 8' W, 22 



0nundarfjord 10 



Adalvik (depth not stated). 

 The Faroe Islands: 7 miles N. by E. of Myggenaes point, depth 57 fathoms 



6 N. by W. of Store Kalso, 60 



Deep hole at north point of Nolso, 100 



5 miles S.S.E. of Bispen, 50 



Sertularella tricuspidata is a circumpolar arctic species which is extremely numerous in arctic 

 waters. From there is penetrates far down into the boreal area (fig. LII) where it is one of the most 

 common species, especially round the Faroe Islands, Iceland, and off West Greenland. Along the east 

 coast of Greenland, however, it is distinctly rare. Its infrequent occurrence off the north coast 

 of Iceland on the other hand, should probably rather be apparent, as the result of insufficient in- 

 vestigations. Along the west coast of Norway, Sertularella tricuspidata goes southward as far as 

 Bergen; according to the literature, it is also met with near the British Isles, but we have no certain 

 data from here, so it would seem that this must be about the limit of its distribution. Bathymetri- 

 cally, it belongs to the littoral region, exceptionally, however, it may, as shown by the find at the "In- 

 golf" St 95, penetrate quite far down into the abyssal. 



60 



',0 



6 oo m. 



2 ooo m. 



Fig. LII. The distribution of Sertularella tricuspidata in the Northern Atlantic. 

 In the hatched regions the literature notes a scattered occurrence. 



'3' 



