PORIFKRA. II. 



85 



ill 



W 



of the axis. The central part of the axis may be somewhat looser, or a little cavity may be found here. 

 The skeleton of the branchlets is formed by a fibre running through the middle of the branchlet; the 

 fibre tapers outward, and has fewest spicules at the outer end. When the branchlets are short, the 

 fibre seems to become thicker and have more spicules. The fibres of the branchlets are in the common 

 way inserted in the spicula-axes of the stem and the branches, between the spicules of these axes; 

 they reach to the middle of the axis, and are spread in the longitudinal direction in a fan-shaped way. 

 In the laver of tissue, which coats the axis, and may be of somewhat varying thickness, only rather 

 few, scattered spicules are found. In the stems and branches the needles are connected by a mass 

 of spongin forming, however, no 

 sheath; under the microscope it 

 appears white and clear, but yet 

 it gives to the axis a yellowish, 

 hyaline appearance. The stem has 

 most spongin and is, consequently, 

 most yellowish at the base. In 

 the fibres of the branchlets spon- 

 gin was not observed. 



Spicula: a. Megasclera are 

 styli, straight or quite slightly 

 curved; they are more or less fusi- 

 form, but most frequently slightly 

 so, only tapering a little towards 

 the head-end; the point is some- 

 what varying, from short, some- 

 times somewhat blunt, to middle 

 long. Their length varies from 

 0-40— o77 mm and the thickness 

 about from o - o22 mm clown to o - oi 1""". 

 The spicules are upon the whole 

 larger and specially thicker in the axis than in the branchlets, but they cannot be said to form two groups. 

 The styli of the branchlets have also a somewhat longer point. Otherwise the length and thickness are 

 in no proportion to each other, and styli are rather frequently found in the axis of the smallest length, 

 but of the greatest, or about the greatest thickness, while on the other hand long styli may be consider- 

 ably fine. In the branchlets and the layer of tissue spicules may be found that are considerably finer 

 than the others and must be developmental forms, they are long pointed. Among the styli, especially 

 in the branchlets, irregular forms are often seen; thus, but more rarely, oxea; more frequently forms 

 are seen with one or more swellings, b. Microsclcra; three forms are found, anisancoras ungmferse 

 and sigmata of two forms and sizes. 1. The ancorEe are of the typical CladorMza-stxuctuie, and have 

 live distinct, lanceolate teeth in either end; one end is considerably larger than the other. The larger 

 end has on either side of the shaft a narrow ala a little longer than the teeth, but comparatively 



Fig. 2. Cladorhiza gelida 11. sp. 



Transverse section. The branchlets being directed a little upward, the fibres issuing 



from the centre are only seen a little way out in the tissue, where they are then 



cut away, while the fibres seen in the branchlets issue more downward, so that 



their bases are not seen. In the tissue embryos are seen. X ca. 32. 



