PORIFER.\. I. 



a piece of the skin is cut off, the meshes of the subjacent skeleton is b\- the microscope seen through 

 the skin, and the ends of the primary fibres project from the nodes. As the transverse fibres of the 

 skeleton are mostly formed of single needles, this skeleton appears as an irregular, mostly imispicular 

 reticulate work, most frequentl\- onl\- in the nodes united b\' spongin. Otherwise no spicules are found 

 in the dermal membrane. The pores are round or oval openings, and are found, single or two or 

 three together, in the meshes formed by the subjacent skeleton; the size is from 0'03""" to o'i2"'"\ 

 Oscnla are round, sometimes a little oval openings of a diameter of i — 4"'"', they are found dispersed 

 ever\- where on the branches in rather great numbers; when the branches are somewhat compressed, 

 they are often set in rows on the edges, and the\- may also be more numerous!}- or almost exclusively 

 found on one side of the branch; but upon the whole the>- are best characterized as dispersed. The}- 

 are often a little projecting, and these projections may grow into papillae of a length of 7'"™ (in whicli 

 cases we have, perhaps, a beginning branch). On the stalk there are no oscula at all. 



The skeleton is chiefly of the same structure as in the foregoing species, and built upon the 

 principle which upon the whole is found in the Chalinhio'. Longitudinal fibres (priinar}- fibres) run 

 longitudinall}- through the sponge, and spread to all sides like a sheaf, reaching to the surface where 

 the}- project a little; the}- are united b}- transverse fibres (secondar}- fibres) into a rather regular net- 

 work. Far the greater part of the longitudinal fibres are poh'spicular, but with far fewer spictiles 

 than in the foregoing species, and also uuispicular fibres are seen; otherwise the fibres are somewhat 

 different with regard to their thickness and the number of spicules, the thickness being about between 

 the thickness of a spicule and 0-09""", and the distance between the longitudinal fibres is ca. o'i2""" 

 — O'ly"'"'; thus the fibres are considerably thinner and the reticular work finer than in the foregoing 

 species. Neither do the transverse spicules here form coherent fibres, but reach onl}- from one longi- 

 tudinal fibre to the next, and are for a great part formed of but one spicule; in the inner part of the 

 sponge they are far from each other, so that the meshes are more or less rectangular, but towards the 

 surface they are nearer to each other, and here the meshes are more or less quadratic. The spongin is 

 not by far so strongly developed as in the foregoing species, and most frequentl}- it forms no distinct 

 sheath or onl}- a ver}- thin one round the spicules of the fibres; in tlie nodes it is distinctly seen; 

 the transverse spicules are not general!}- quite surroimded b}- spongin, but onl}- cemented at the ends. 

 Besides the skeletal tissue thus constituted, some fibres are seen here and there running longitudinally 

 along the branches witliout going to the surface, which filjres mav divide and anastomose; the}- are 

 a little stronger than the regular longitudinal fibres, and have more spongin forming a distinct sheath. 

 Towards the base of the sponge the amount of spongin is greater, and the spicules of the fibres are 

 here surrounded b}- a distinct spongin-sheath. In the hard, solid stalk the amount of spongin is ver}- 

 considerable, and at the same time it passes from colourless to yellow; the intervals between the 

 fibres are here very small, and tlie whole mass forms a very solid tissue. 



Spicula are straight ore most frequentl}- slightl}- curved o.xea, exenl}- tapering. The length is 

 between o-ii8 and o-i48""", and the thickness o-oo8 — 0-0114'"™. Shorter and finer needles, to quite fine 

 ones, developmental forms, are also found in small numbers, as also a few styli. 



Although Vosmaer does not give the length of tlie needles, the species is so well consistent 

 witli his description and pictures that I think the determination to be sure; \'osmaer seems to attach 



\ 



K. 



