HYDROIDA II 



"Thor" 66i 9 ' N, 23=27' W., depth 115-120 metres. Variety. 

 65*52' N, 23-58' W, 62 



6 3 3 o' N., 2oi 4 ' W., 80 



Greenland: Davis Strait, IOO fathoms (without further details) 



Iceland: 5 miles E. of Seydisfjord, - 185 



Ingolfshofdi g'/ 2 miles in N. by E.'/sE. (depth not stated) 

 Vestmano, depth 50 fathoms 

 Skagi, 40 metres 



6 miles W. of Iceland (without further details) [labelled Diphasia rosacea] 

 0nundarfjord, depth 10 fathoms | _ ] 



6539' N., 2825' W., depth 553 fathoms. 



Between Iceland and The Faroe Islands: depth 270 fathoms (without further details). 

 The Faroe Islands: 8 10 miles N. of The Faroe Islands ( ) 



7 miles N. by E. of Myggenses point, depth 57 fathoms 

 6 N. by W. of Store Kalso, 60 



Deep hole at north point of Nolso, 100 



Boronaes 13 miles in N. 75 W. 30 



16 miles E. by S. of south point of Nolso 80 



It may be a question whether Diphasia fallax cannot exceptionally be confused with Diphasia 

 Wandeli Levinsen, if the latter species, as Saemundsson opines, can occur with only two rows of 

 hydrothecee on the branches. There are also in the present material colonies of Diphasia fallax dif- 

 fering in appearance, so that there is some ground for further considering the point. 



Saemundsson (191 1 p. 97) mentions having found colonies of Diphasia Wandeli with only two 

 rows of hydrothecse on the branches, and with female gonothecee, which, however, from his drawings, 

 agree entirely with Diphasia fallax. According to a footnote in SDemundsson's work (1911 p. 98) 

 Levinsen should, after seeing the colonies, have expressed as his opinion that they must rather be 

 regarded as aberrant colonies of Diphasia fallax than as representatives of Diphasia Wandeli. Now 

 Saemundsson points out, in the same place, that a colony of Diphasia Wandeli from the Norwegian 

 Sea, which he has had occasion to study, had on the basal parts of eight of its branches only two 

 rows of hydrothecae, while the outer parts of these branches, and all the remaining ones throughout 

 their length, had three rows of hydrothecae. This reminds one not a little of the aberrant Thujaria, 

 which is further described in "Fauna artica" (Broch 1909 p. 177). As the colony described by Sae- 

 mundsson is sterile, it cannot be determined with certainty. It is probably a Diphasia Wandeli, but 

 it might also be imagined that it could be a mutant of Diphasia fallax, though this is less likely to 

 be the case. Typical female colonies of Diphasia Wandeli with gouothecae have not yet been found ; 

 as to the males, we know that they differ from Diphasia fallax in having eight instead of four distal 

 spines on the gonothecae, these eight spines being arranged in pairs. It is therefore impossible to say 

 with certainty which species Saemundsson had before him, as long as typical and fertile female 

 colonies of Diphasia Wandeli have not yet been found. Saemundsson's colonies form, moreover, 

 only the extreme link in a continuous variation series, of which the central one is Diphasia fallax. 



