For several years I have felt the desire of going to Plymouth in order to gain practical knowledge of the excellent methods for rearing pelagic laræ, of marine animals, which have been worked out there, especially by the Director of the Marine Biological Laboratory, Dr. E. J. Allen. I was therefore very glad to receive last year an invitation from Dr. Allen to come and stay some time at his laboratory, and having got a grant for this purpose from the Carlsberg Fund and from the Danish Government, I had at length the desired opportunity.

The time I spent in Plymouth—from June 10th to July 15th this summer (1913)— was long enough for learning the methods, but, unfortunately, too short for having the full profit of my rearings, because several of the larvæ, take a longer time to reach their full size and still more to pass through metamorphosis. However, the results attained are not unimportant.

No less than six different species of Echinoderms were reared to a more or less advanced stage of development, according to the date at which fertilization could be undertaken, and according to the rate of growth of the different larval forms. These six species are: Asterias glaciallis, Luidia ciliaris, Ophiactis Balli, Ophiocoma nigra, Spatangus Purpureus, and Holothuria nigra. Fertilization of Echinocardium flavescens was also undertaken, but unfortunately the whole culture was destroyed by an accident, and no material was got later on of the species. Some other forms, the development of which I wanted likewise to study, e.g.Echinocardium pennatifidum, Amphiura (Ophiocnida) brachiala, Ophiopsila aranea, were not ripe at that time or sufficient material could not be got.