IN THE SOUTHERN NORTJi SEA. 31 



1 may particularise Natlca aldei'i, Oj^helia liviacitta, Fectinaria 

 koreni, and Echmocyamus pusilli(s. In stations with no character- 

 istic animals, I have attached importance to these species, which 

 in conjunction with the depth, condition of bottom, and scarcity 

 of animals, all point to the" Fe?ms "-conniiunity. The occurrence 

 of Abra prismatica and Alactra elliptica in some stations is in- 

 dicative of the " c/ee/^ leiiifs" community, Avhich has been found 

 in the deeper parts of the Danish " /"e^ms "-community ; but as 

 the characteristic species EchinocardiumfJavescens and Spatangus 

 purpureus, so typical of this community, are wanting, I can for 

 the present only designate these stations as " VenifjS "-stations in 

 general. 



Stations 12-15 are cliaracterised by such animals as Amphiura 

 Jiliformis, Turritella terehra, Axhius Jiexuosus, and Ecliinocclrdium 

 cordatum. Stations 12 and 13, however, are transitional from 

 the " Venus "-community, containing several of the characteristic 

 animals of this community but mostly as small specimens, and 

 only a few Amphiura. But as a whole these stations must be 

 reckoned as belonging to the " Echinocardhmi-filiformis " com- 

 munity. The bottom, consisting previously of hard sand or 

 gravel, is here softer, mixed with detritus and clay. This 

 community is not represented in Dr. Petersen's hypothetical 

 chart in Kept. XXII. (on this point see remarks in Rept. XXIII., 

 1915, p. 10, at the top) ; it wns charted in Rept. XXI. as the 

 '■• Echinocardi'wn- Turritella "'COTCLV[i\\nity^ \\A-iic\\ is widely distri- 

 buted in the Kattegat, Skagerrak, and Christiania Fjord. Without 

 doubt it will later become appai'ent that this community covers 

 big areas in the deeper parts of the North Sea. 



The last station, Xo. 20, in the neighbourhood of Graa-deep 

 light-vessel, is a typical " ^4 &ra "-station, with Abra alba, Rucida 

 niiida, and fragments of Echinocardium cordahmi. The existence 

 here of an " ^4 6r« "-community was already proved in 1912 by 

 some few samples taken by the ' Michael Sars ' in the neighbour- 

 hood of Graa-deep and Horns Reef. 



We have thus met with four different communities : — ^.'■'■Macoma 

 6«?iic« "-community along the shore in Lowestoft Harbour; a 

 " ^e?^'^<;s "-community in the greater part of the investigated area 

 of the Xorth Sea, with depths most frequently between 9 and 

 38 m. and a pure sand and gravel bottom ; an Echinocardium 

 filiformis community in depths of 38-41 m. with a dark, soft 

 sandy bottom ; and finally, an ^4Z»j'«-community near the shores 

 of Jutland. Possibly this last-named community also will be 

 discovered near Lowestoft, as in a single sample taken with the 

 grab in Lowestoft Harbour, in a depth of 3 m. at ebb tide, I found 

 one adult Abra alba. But it is beyond doubt that the greater part 

 of the bottom fauna of the North Sea below 38 m. will turn out 

 to belong to " T'evMts "-community, as indicated in Dr. Petersen's 

 chart. This is confirmed also by the few samples taken in former 

 years with the bottom sampler oft' Thyboron (Report XXL, 

 Appendix pp. 63-G6), and by the numerous samples which 



