„Q PORIFERA. I. 



sometimes irregularlv curved; they are of aboixt equal thickness in their whole length; the points are 

 somewhat varving in length, but are always rather short. The length of the oxea is Isetween 

 0-137— o-i66"'™, and ma\- in a few cases reach oijS"™. The thickness is rather varying, and the longest 

 ones are not the thickest; it \aries between 0-003 — 0-007"™, the thicker ones being most frequently met 

 with. b. Microsclcra\ only one form of microsclera is found, viz. toxa; they are all fine, but very much 

 varying in length, and also their form is somewhat varying, and rather frequently somewhat irregular; 

 their curve varies very much, so that they may be from almost straight to rectangular; in many of 

 them the ends are a little inclined backwards, while in others this inclining is wanting. They are of 

 equal thickness in their whole length, and upon the whole their appearance is very simple. Their length 

 is from ca. 0-028 up to 0-107™'". The thickness is ca. o-ooi"™or somewhat more in proportion to the .size')- 

 Locality: Juliauehaab (inspector Ryberg). We have in all seven specimens or fragments, all 

 growing on a branched Lithothamniou. 



6. G. proximus n. sp. 

 PI. XIII, Fig. 12 a— b. 



Cntsf-shapcd, incnistiiig. The dermal membrane titiu. the nodes of the skeleton belo7i< make it 

 slightly granuloKS, and if is slightly shaggy from projecting spicules. The skeleton (or by far the greatest 

 part of it) is unispicular, and forms triangular or irregular meshes. Spicula: Megasclera oxea o-i4g 

 — o-iS4"""; microsclera Jine toxa. 0-028 — o-ioy'""'. 



Of this species we have only two small specimens growing as incrustations on Balanoid shells; 

 the greatest extension is 17"", but the specimens are scarcel\- quite whole; the thickness is ca. 4™"'. 

 The surface is slightly granulous, and spicules project. The colour (in spirit) is a light gray. The 

 dermal membrane is thin and transparent, and the spici;les below it form a reticiilation of mosth' tri- 

 angular meshes; the nodes rise a little which is the cause of the granulous appearance of the surface; 

 besides spicules frou: the skeleton project through the skin, and so it is slightly shaggy. Pores are 

 found in large numbers in the meshes, and are measured of a size from 0-017 — o-i8""". 



The skeleton is unispicular, and consists of triangular or irregular meshes, polyspicular fibres 

 are perhaps also found. The part of the skeleton immediately below the skin forms rather regular, 

 triangular meshes that may be seen through the skin as a reticulation. The ends of the spicules are 

 united by a clear, copious mass of spongin. 



Spicula: a. Alegasclera are oxea; the}- are slighth- curved, sometimes almost straight, of equal 

 thickness in their whole length, and more or less shortly pointed ; the points are often roiinded, and 

 then sometimes provided with a little mucro. The length is between 0-149 — 0-184'"'"; the\- are rather 

 thick, the thickness varying from ca. o-oo6 — 001""". Finer needles, developmental forms, occur in small 

 numbers, b. Microsclera : ov\\ one form of microsclera is foiind, \iz. toxa; they are of quite the same 

 form as the bows in the preceding species, and they are also very fine, and vary in size and form; 



') As the bo-«-s van- very much with regard to the degree of their curving, and as also the megasclera are sometimes 

 rather strongly curved, spicules may be found, with regard to which it cannot be decided, whether they are bows or deve- 

 lopmental forms of oxea. 



