PORIFKRA. II. 119 



says that it sits on serpula-tubes, muscles, stones etc. The stalk passes into a rather thick, more or 

 less fan-shaped leaf; this leaf is thickest in the middle, but becomes thinner towards the edge. The 

 largest specimen has a height of ca. o,o mm , and the leaf has a similar breadth. The greatest thickness 

 of the leaf in the middle is ca. ij mm , the stalk has a height of 20" ,m and a thickness of fully io mm . 

 The other specimen is a little smaller, and the leaf especially is less broad. Of the small specimens 

 one has a height of 24 mm , half of which is a stalk scarcely 2 mm thick; this specimen may more properly 

 be called club-shaped than leaf-shaped, its upper part having a breadth of o, mm and a thickness of 

 6 mm . The smallest specimen is only i2 mm high, of which the stalk makes about the half. This specimen 

 is quite club-shaped and has a greatest breadth of 3 mni . The consistency is rather loose, but the stalk 

 is considerably harder. The colour (in spirit) may be given as light brownish gray. Of the surface 

 I dare, on account of the condition of the specimens, say nothing with certainty, but doubtless the 

 ends of the fibres project making it sparingly shaggy. The dermal membrane^ to judge from the few 

 places of the sponge where it is kept, is a thin film provided with scattered oxea and with very 

 close-lying chelae. Oscula and pores I have not been able to observe on my specimens, but on a young 

 club-shaped specimen, kindly sent me by Miss E. Arnesen, an osculum was found at the top, as has 

 been figured by the authoress 1. c. Rather close-standing canals run through the sponge continuing 

 from the surface horizontally inward or somewhat downward; these canals convey an impression of 

 being larger on one side than on the other, and perhaps therefore, in the grown, leaf-shaped sponge 

 pores and oscula have been localized each on their side of the sponge. 



The skeleton consists in the stalk of close-lying, strong, polyspicular fibres connected by power- 

 ful spicula-bundles, so that a solid network is formed. This skeleton forms the greater part of the 

 stalk, only a little network of thinner fibres being found on the outside. From the stalk the fibres 

 continue into the leaf and bend to the sides in a fan-shaped way, branching and by degrees becoming 

 thinner; thus the outer branchings form the edge of the sponge. The fibres, however, bend also and 

 ramify in a fan-shaped manner towards the two surfaces of the sponge, where accordingly their outer ends 

 projects everywhere. Thus these primary fibres have a rather regular course, and the distance between 

 them is also rather equal, ca. 0-29— cr4 m,D . The fibres are thickest in the middle of the sponge and 

 may here reach a thickness of o-2 mn '; then they consist of many spicules alongside, but through their 

 outward course they become thinner and go down to a thickness of only a few spicules, in a few- 

 places even they consist of only two spicules alongside. In the stalk the fibres may reach a thickness 

 of o-27 mm . The primary fibres are connected by transverse spicules most frequently single, only some- 

 times two or three together; the transverse spicules are placed perpendicularly on the primary fibres, 

 but otherwise without regular intervals, they do not form continuous fibres. In the skeleton a distinct 

 but clear and white mass of spongin is found, especially distinct in the nodes. It may in some places 

 be rather copious and entirely coat the fibres, but this does not seem to be the common case. In 

 the stalk it is more copious, here it coats the fibres entirely, and is of a yellowish colour. 



Spicula: a. Megasclera are oxea, divided in two rather distinctly separated sizes, of which the 

 larger ones form the main skeleton, while the smaller ones are found in the dermal membrane. The larger 

 oxea are evenly curved, sometimes the bend is somewhat sharper and localized to the middle of the spicule. 

 The points are evenly pointed and of middle length. The length varies from ca. 041— e>-55 mm , and the 



