HYDROIDA 11 



71 



The gonotliecse are attached to the apophyse beside the sessile sarcotheca. Fully grown gon- 

 angia have not yet been found. 



Material : 



"Ingolf" St. 27 64°54' N., 55^10' W., depth 393 fathoms 3,8° 



— - 34- 65°! 7' N., 54^17' W.. — 55 _ 

 Greenland: Davis vStrait (without further details] |type specimens of Plumularia groenlandica\ 

 Iceland : Ingolfshofdi q>/\ miles in N. by E. 7., E.. depth 53 fathoms. 



Levinsen (1893 P- 63) gives a very detailed description of this species, which he incorrectly 

 regards as different from vSars's Plnmnlan'a gracillium. He has however, in common with others who 



200 m. .._„ 600 m. .. looo m. 2000m. 



Fig. XXXV. The localities of Polynemertesia gracillima in tlie Northern .-Atlantic. 

 In the hatched region the occurrence according to the literature is coniuion, although scattered. 



have investigated the species, overlooked its typical sessile sarcotheca on the apophyses (fig. XXXIV) 

 It is noticeable that a mamelon occars not onh- on the primary but on all the apophyses in the colony. 

 The idea that it should, as Nutting (1900) believes to be the case with other species, form the point 

 of origin of the gouothecae, is due to inadequate investigation; the gonothecjE have their point of 

 attachment by the side of this sarcotheca. Levinsen 's description incorrectly gives the impression 

 that he has had grown gonothecoe before him at the time; they are, however, only quite young stages, 

 and grown gonangia have thus not been described for this species. 



Polynemrrfesia gracillinia is plainly a southern visitor to the northern waters, and has strangely 

 enough not >et been recorded in the British waters (fig. XXXV j. The "Ingolf was able to furni.sh 



