HYDROIDA II 



21 



again, we find in the shape of the hydrotheca; according to Kramp, (igii p. 376) the margin of the 

 hydrotheca in Graiinuaria abictina — in contrast to Grammaria immcrsa — always cnrves outwards 

 slightly; in forma brcvicyatha, on the other hand, this is only quite exceptionally the case, and by far 

 the greater number of hydrothecce show no indication of outward curvature in the margin. Kramp 

 has (1. c.) pointed out another feature which is here of more importance. In forma brcvicyatha^ the 

 hydrotheca aperture is almost invariably turned somewhat obliquely ui:)wards, not as in forma typica, 

 where the plane of the aperture is parallel with the axis of the branch, or in Grammaria immersa^ 



b QO rn 



.._._. 2000 m. 



Fig. VI. Localities of Giannnaria abictina (forma brevicyatha -|-) in the Northern Atlantic. 

 In the hatched region the literature notes a common, although scattered occurrence. 



where the opening is even turned slightly downwards. In forma brevicyatha, only the few large hydro- 

 thecae have a plane of aperture parallel with the axis of the branch. 



Grammaria abictina is a typical arctic-boreal species, recorded also in a single instance (Bil- 

 lard, 1904 p. 164) from the north of France. It may at times penetrate down to great depths, as for 

 instance at the "Ingolf St. 92, where it reached 976 fathoms, the greatest depth hitherto recorded for 

 this species. Otherwise it is chiefly found (see fig. VI) in the deeper parts of the littoral regions of the boreal 

 and arctic area. Grammaria abictina is also apparently an Atlantic species; it is known from the east coast 

 of North America, to Taimur, but has not hitherto been recorded from about Bering Strait or the 

 Pacific. If, however, it should prove correct that Grammaria. scandens Stechow is a synonym for 

 Grammaria abietiiia, then it must be classed among the circumpolar species. 



