. The Danish Ingolf-Expedition. Scientific expeditions; Arctic Ocean. 84 PORIFERA. spicules liere forming fibres which run stellately to the top or the middle of the cone, but also here the fibres run below the dermal membrane and not in it, and the dense layer of chelse continues just to the centre of the cone. The main skeleton consists in the ordinary way of perpendicular acantho- styli with their heads on the substratum; the longest styli reach up to the dermal membrane. At the base a small amount of spongin is present. Spicula: a. Megasclera. i. The skeletal spicules are acanthostyl
. The Danish Ingolf-Expedition. Scientific expeditions; Arctic Ocean. 84 PORIFERA. spicules liere forming fibres which run stellately to the top or the middle of the cone, but also here the fibres run below the dermal membrane and not in it, and the dense layer of chelse continues just to the centre of the cone. The main skeleton consists in the ordinary way of perpendicular acantho- styli with their heads on the substratum; the longest styli reach up to the dermal membrane. At the base a small amount of spongin is present. Spicula: a. Megasclera. i. The skeletal spicules are acanthostyli; they are slightly curved, generally nearest the base, and they are somewhat densely spined in their whole length; the head is round and generally well marked; the spines on the head are straightly radiating, on the shaft they are reclined. The spicules vary much in length, but as all intermediate sizes are present they are not divided into two groups; the length is o-i2—0*38mm and the diameter of the head 0-02—0-03 mm. 2. The dermal spicules are straight and very slightly fusiform; they may be termed subtoruota, but generally one end is rounded so that they are tornostrongyla and also both ends may be rounded, the spicules thus being strongyla; they are distinctly polytylote. The length is 0-27—o-38mm and the diameter croo6— o-oo8mra. b. Microsclera are chelse arena tee of a very characteristic and remarkable shape; the shaft is very strongly curved, sometimes to so high a degree that its end-parts form two nearly parallel arms; on the middle of the hinder side of the shaft there are a number of strong spines. Also the shape of the end-parts of the chela affords great interest; the tooth is protruding greatly forwards, but it is formed almost entirely of the strongly developed falx, while there is nearly no plate, the falx only being somewhat thickened at the front edge; the alse are also very interesting, they quite resemble the falx in shape and they are of the sam
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectscienti, bookyear1910
