64 PORIFER.A. II. 



.seen in the skin, most frequently of a size of about o-oc/ 11 " 1 ; they belong presumably to the incurrent 

 system; the excurrent system opens possibly in the branches, which would then act as oscula. 



The skeleton is chiefly arranged as in A. bikamatifera. It consists of a spicula-axis, which is 

 not compact, but formed by a number of fibres arranged in a circular way round the middle; between 

 these fibres the short fibres or spicula-bundles that form the skeleton of the branches are inserted, so 

 as to meet in the middle. The fibres of the branches may often be seen not to be solid, but their 

 inner part is hollow, so that they do not pass to the middle as solid fibres, but some of their spicules 

 are inserted in one place of the axis, some in another place. In the periphery of the axis no spicules 

 are found here, as was the case in biliamatifcra, the dermal membrane is supported and distended only 

 by the skeleton of the branches; at most a few scattered spicules are found. In the lower part of the 

 stalk where spicules project all round, no circularly arranged fibres are found, but the spicules of the 

 axis are seen in a transverse section to be more evenly distributed, or irregularly grouped, and the 

 projecting spicules are inserted between them. In the axis a small amount of spongiu is found. 



Spicala: a. Megasclcra are styli; most frequently they are straight, more rarely quite slightly 

 curved; only the shorter styli, and especially the quite short ones occurring down in the stalk, are 

 always more highly curved. The long styli most frequently, but to an almost imperceptible degree, 

 become thinner a little below the rounded end. The opposite end tapers gradually to a long point, 

 which is sometimes, especially in the thicker spicules, more abruptly pointed at the extremity. There 

 is no difference between the needles of the axis and those of the branches, but towards the base the 

 needles of the axis get shorter, and here they occur of a particular form as short curved styli to which 

 especially those needles belong that project and make the stalk shaggy. These shorter, curved styli, 

 to be sure, occur here as a particular form, but they are connected with the other styli by a series of 

 transitional forms. If all sizes are included the length varies from 1-5™™ quite down to o-238 m '"; if the 

 lower part of the stalk is excluded, o'6 ,n,n may be given as about the lower limit, and the upper limit 

 of the basal spicules may be put about at o-4 ,mn , but, as before mentioned, the two forms pass into 

 each other. If all the forms are included the thickness is between o-oo7 mm and o-02i mm ; it is tolerably 

 proportionate to the length, and with regard to the short curved styli it does not exceed 0-015"™. 

 Some fine to quite fine developmental forms are seen. b. Microsclera ; these are anisochelas palmatse 

 and forcipes. 1. The anisochelse are of the type of the subgenus and are constructed in quite the 

 same way as those of the preceding species. Their length is o-oi4 mm , varying very little to both sides; 

 in one large and robust specimen they reach a length of o-oi7 mm ; the breadth is o-oo7 mm . 2. Forcipes; 

 these are longer and finer than in the preceding species. They are thickest above, and may here, when 

 seen from the side, show a slight, tubercle-shaped swelling. They are of a characteristic form; from 

 the curve the legs continue parallelly or in a slightly diverging manner, then follows a bend in such a 

 manner, that the ends converge (PI. XI, fig. 6d) 1 ). The legs end in a small, distinct knob; they decrease 

 in thickness outward, and in their outer part they are so fine, as to be only discerned with difficult)'. 

 The length is rather constant, and was measured to 0-050 — o-056 mm . As mentioned, they are very fine, 

 the thickness of the legs does not exceed o-ooio mm above, and towards the point they are much finer. 



*) If specimens are sometimes seen with their legs bent in other ways, this is, no doubt, only owing to the fact that 

 they are under pressure in the preparation. 



