Deep-sea Pycnogonida collected by the “Cirrus” in the Northern Atlantic

Two Pycnogonida only have been collected during the cruises of the meteorological vessel ”Cirrus” in deep plankton tows, but both specimens, each belonging to a different species, proved to be of considerable interest. I am indebted to Mr. C. L. Bekkering and Mr. S. D. Koning, who presented this precious material to the Zoölogisch Museum, Amsterdam. The one specimen belongs to a relatively well-known species, Callipallene acus (Meinert, 1898). On the basis of this material, our knowledge on the external morphology of this species, more particularly on the polymorphism in the legs, could be extended