HYDROIDA II 169 



Sterile colonies of this species with almost or entirely smooth margin may at times present a 

 certain resemblance to Laomedea flexuosa, and have frequently been confused with this species by 

 Ssemundsson. — Nutting (1915 p. 73) endeavours to revive Obelia flabellata Hincks on the ground 

 that the extreme branches of this species exhibit dichotomous ramification, whereas in the present 

 species they are "flabellate"; unfortunately, however, he does not further explain the difference between 

 the two terms. In the present colonies, both might often apparently be applied to the same branch. 

 Nor does his other distinctive character, the fact that the branches in Obelia longissima are "regularly 

 alternate" while those in Obeiia flabellata are "alternate or opposite" give us any sound basis to work 

 on. Bonnevie (1899 p. 71) is undoubtedly right in uniting the two species, and they cannot be 

 revived on the strength of what Nutting here seeks to show. 



Laomedea longissima appears to be a cosmopolitan species, albeit the data on record from 

 tropic-subtropical waters are but scanty. The species belongs to the upper third of the littoral region, 

 and goes far up into arctic waters, where it has a circumpolar distribution. In the area investigated 

 (fig. LXXXVI) it appears to be entirely lacking in East Greenland waters, but is otherwise fairly re- 

 gularly met with on all coasts. 



Laomedea hyalina (Hincks) Levin sen. 

 1866 Gonothyrcea hyalina, Hincks, On new British Hydroida, p. 297. 

 1893 Laomedea — Levinsen, Meduser, Ctenophorer og Hydroider, p. 28. 



Finely built upright colonies with monosiphonic main stem, the latter being, like the main 

 branches, generally brown in colour. The colony often assumes a bushy appearance, owing to irre- 

 gular ramification. The hydrothecae are carried on short ringed stalks proceeding from the branch 

 apophyses; the latter are set in a plane on the branch directed alternately to either side. The hydro- 

 thecae are slender, inversely conical to cylindrical, tapering somewhat more at the basal part toward 

 where the stalk begins; they are twice to three times as long as broad. The hydrotheca margin is 

 furnished with low teeth, having a slight, often almost imperceptible median sinus in their distal 

 end, which is cut off almost straight, so that they are divided into two denticles; from this sinus a 

 slight furrow runs for a varying distance down the hydrotheca on its outer side. The basal chamber 

 is small, bounded at the top by a thin, but well developed diaphragm. 



The gonothecse are borne on short, ringed stalks, proceeding from the apophyses beside the 

 hydrotheca stalks. They are inversely conical, cut off straight at the distal end, without neck. The 

 gonophores develope into crypto-medusoid meconidia, which extend out from the gonotheca without 

 breaking away; the larval development takes place in the interior of the meconidium. {Gonothyraa 

 medusae). 



Material : 



"In golf St. 34, 65°i7' N., 54°i7' W., depth 55 fathoms. 



"Thor" 66°23' N., i4°24' W., — 45 metres 



65°52' N., 23°58' W., — 62 — | labelled Laomedea Loveni] 



64°i6' N., 22°i7' W., - 50 



The Ingolf-Expediiion. V. 7. 



