IO HYDROIDA II 



Forma elegantula: 



"Ingolf" St 3, 6335' N., io24' W., depth 272 fathoms, 0,5 



- 29, 6 5 34 ' N, 54 3 i' W, 68 0,2 



- 31, 66 35 ' N, 55 54' W., 88 1,6 



- 33, 6 7 5 7' N, 55 3 o' W, - 35 0.8 



- 34, 6 5 i7' N, 54 i7' W., 55 



Greenland: Davis Strait (precise locality not stated) depth 100 fathoms. 

 Akudlek (no further data) 



Egedesminde ( - - ) 



Mouth of Ameralikfjord ( - - ) 



Sukkertoppen, on Boltenia ( - ) 



Jakobshavn ( - - ) 



Hurry Inlet, depth o 7 fathoms (East Greenland Expedition) 



57 (- ) 



Harry Land 20 ( - ) 



Iceland: "Thor" 52 miles E. of Langanes 

 Skjalfaudi Bay, depth 28 fathoms 

 9 miles N. 74 E. of Hornet, east coast of Iceland, depth 38 fathoms 



64i7,5' N., i444 r W., depth 40 fathoms, 5,12 

 The Faroe Islands: 6i4o' N., 74o' W., 135 



6 miles N. by W. of Store Kalso, depth 60 fathoms 

 Kara Sea "Dijmphna" (labelled Lafoea fruticosa). 



The distinguishing features between Lafoea gracillima and Lafoea fruticosa may often appear 

 very insignificant, and in arctic waters especially one may often be in doubt as to whether a specimen 

 is a robustly built colony of L. gracillima forma elegantula or a finely built L. fruticosa forma genuina. 

 The feature emphasised by Bonnevie (1899 p. 61) viz: the number of spiral turns on the stalk, is in 

 particular extremely variable in somewhat larger colonies, and it is likewise found that the angle 

 between stalk and mother stolon, especially among creeping colonies, is little to be relied on. Another 

 feature, however, to which I have long since drawn attention (1907 p. 7) seems to be more constant, 

 and will also according to the present material serve to determine the identity of species. The feature 

 in question consists in the fact that the abcauline concave side of the hydrotheca in -Lafoea gracil- 

 lima lacks the basal convexity found in Lafoea fruticosa, and that the margin of the hydrotheca on 

 this side is never curved outwards in Lafoea gracillima, in contrast to Lafoea fruticosa, where the lower 

 (concave) side of the hydrotheca is thus always more or less S-shaped in profile. 



Among the synonyms for Lafoea gracillima we have also here included Lafoea pygmcea pars. 

 Jaderholm (1909 p. 80) includes this species as a synonym under Calycella syringa, and he is un- 

 doubtedly right in so doing. According to Hincks (1868 p. 205) the original drawings by Alder 

 exhibit indications of opercular formation in the hydrotheca here and there, a point which beyond question 

 suggests this species. On the other hand, Hincks's description is entirely in agreement with the 



