32 ON ANIMAL COMMUNITIES IN THE SOUTHERN NOllTH SKA. 



according to the friendly communication of Dr. Rassell, have 

 been taken with the bottom sampler this year on the Dogger Bank. 



As to the number of animals per square mile, it will be seen from 

 the accompanying list (pp. 28-29) that, setting aside the Epi-Fauna, 

 we have to do with a comparatively poor fauna. For instance, the 

 •' Fewts "-stations together give only 26-3 gr. per 2-6 sq. m. or 

 lO'l gr. per sq. ra. But on the other hand, most of the animals 

 are useful as being excellent fish-food. Compared with the 

 " Fe?^^ts "-community in the Kattegat (Rept. XXI., Appendix, 

 pp. 9-13), it will be seen that the apparent richness of the latter 

 is due mainly to big echinoderms such as Echinocardmm and 

 Ophiiirids, or big lamellibranchs such as Cyprina or Aiacoma 

 calcarea, useless as fish-food. 



On the other hand, we may find in the North Sea as well as in 

 the Kattegat small areas within the " Fe?iws "-community, in- 

 habited by large numbers of Mactra suhtruncata (see, for instance, 

 St. 8 in Rept. XXL, Appendix, p. 65, with over 2 kg. per sq. m,, 

 also among the samples taken by the ' George Bligh ' this year 

 on the Dogger Bank, several of which contain some hundreds of 

 speciinens per 0*2 sq. m.). It would be of the greatest interest 

 to know something further about the distribution and abundance 

 of this most important food species, at different times of the year 

 and at different places in the North Sea. At the same time 

 continued investigation of the stomach-content of the food-fishes 

 is called for, following up the excellent work of Todd (Second 

 Report on the Food of Fishes, North Sea Investigation Committee, 

 Southern Area, Second Report, Part I., 1904-5). From his 

 paper it would appear that the food of the fish in the south- 

 western North Sea is composed mainly of " Venus "-animals. 

 But, as mentioned above, we have in the deeper central parts of 

 the North Sea an extended area, which is still a terra incognita 

 and still awaits charting. 



