. The Danish Ingolf-Expedition. Scientific expeditions; Arctic Ocean. 8o PORIFKRA. II. s swelling, as described and figured by Sars. Sars says that the branchlets are generally arranged in a circular way, my material is too much damaged to enable me to decide this fact with certainty. The largest of my specimens is, inclusive of the root, 75",m high, but the specimen is not quite entire above; the longest branch is 25mm, and the thickness of the stalk is fully 2mm. The small unbranched specimens are 33mm high. Thus this species would seem not to reach any considerable size; Sars gives the
. The Danish Ingolf-Expedition. Scientific expeditions; Arctic Ocean. 8o PORIFKRA. II. s swelling, as described and figured by Sars. Sars says that the branchlets are generally arranged in a circular way, my material is too much damaged to enable me to decide this fact with certainty. The largest of my specimens is, inclusive of the root, 75",m high, but the specimen is not quite entire above; the longest branch is 25mm, and the thickness of the stalk is fully 2mm. The small unbranched specimens are 33mm high. Thus this species would seem not to reach any considerable size; Sars gives the height of his specimen to 6omm, and the specimens from the North Sea and the Gulf of St. Lawrence, mentioned by Schmidt and Lambe , were smaller')- The colour of the sponge '(in spirit) is white or slightly yellowish, often a little transparent; Sars states the colour in fresh speci- mens to be transparently yellow. On account of the axial skeleton the sponge is rather stiff and not very flexible; the outer layer of tissue is soft, and the branchlets are flexible. The surface is smooth, and only at the end of the branchlets projects the supporting fibre. No distinct dermal membrane was seen. Pores were not observed with certainty; here and there on the surface small circular openings were seen, but on account of the bad state of the material I dare not with certainty regard them as pores. Oscula were not found either. Nor have, as it is well known, pores and oscula been mentioned before in this sponge2). The skeleton consists, in the stalk and the branches, of a compact, pohspicular axis, the needles of which are parallel to each other and to the longitudinal direction; the axis of the stalk, however, is in the lower part somewhat spirally twisted. Below, the stalk, as mentioned, ends in a highly branched root, the branches of which taper more and more, till they end almost with only one spicule, or with a couple of spicules alongside each other. The branches on the stem a
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