13° 



HYDROIDA II 



be more common in the Scottish waters than is generally supposed from the data obtained; he con- 

 siders it likely that it may have been confused with young colonies of Sertularia argentea. This sup- 

 position will probably prove correct, as the species is fairly common along the west coast of Norway, 

 and penetrates right down to Rohuslan. It is also not uncommon at the Faroe Islands and Iceland; with 

 regard to the latter locality, it is scarce on the south coast, and apparently not very frequent on the 

 north. From East Greenland, it is known only by a single find far to the north, whereas it has been 

 met with several times in West Greenland waters. (Fig. L-XVUI). 



Sertularia Fabricii Levinsen. 

 [893 Sertularia Fabricii, Levinsen, Meduser, Ctenophorer og Hydroider, p. 48, pi. 6, figs. 14—17. 



Upright colonies with not very pronounced, monosiphonic stem, the hydrothecse and branches 

 forming dextrorse spirals. Of the basal branches, only the basal internodium is retained, the remainder 



falling away. The stem is divided into iuteruodia, each bear- 

 ing a basal branch, alternating in each of the two hydro- 

 theca series; between two successive branches in the same 

 hydrotheca series the stem has normally three hydrothecse 

 the lowest in the branch corner. The broad plane of the 

 branches is horizontally set. The branches are secondarily 

 ramified dichotomically, and divided into internodia of vary- 

 ing length. The hydrothecse are set in two rows, sub- 

 alternately or alternately placed; they are deeply imbedded 

 the free part of the adcauline wall is between one-third and 

 one-sixth the length of the hydrotheca, or between one-half 

 and one whole opening diameter. The distal part of the hy- 

 drotheca diverges only slightly from the axis of the branch 

 ( hi the spiral branches, the hydrothecse tend more or less 

 towards unilateral arrangement on the upper side of the 

 branch. The hydrothecse are of equal breadth in their imbedded part, and narrowing slightly in the 

 free portion towards the opening; the margin of the latter has two short and broad lateral teeth; the 

 abcauline opercular plate has a large free distal part. 



The ^niiothecse proceed from below the base of the hydrothecse on the upper side of the branch. 

 They are slender, reversely conical, somewhat flattened in transverse section, the narrow sides as a 

 rule running out each into one short, strong tooth; more rarely, one tooth --or both — may be 

 lacking. The gonotheca has a broad distal aperture, furnished with a short, often rudimentary cy- 

 lindrical neck. 



Fig. I, XIX. Sertularia Fabricii from Godthaab. 



a Ilvdrnthecae from the distal part of a branch. 



h Hydrothecse from the proximal internodium of 



the same. (X 40). 



"Ingolf" St. 2, 63°o4' N., o,°22' W., depth 262 fathoms 



- 3, 63°35' N., io°2 4 ' W., 272 



- 4, 64°o7' N., n°i2' W., 237 

 nland: Store Hellefiskebanke, depth not stated 



Godthaab, depth 30 — 40 fathoms 

 Julianehaab, depth not stated 



5.3 

 o,5° 



Levinsen's type specimens. 



