1 84 



PORIFERA. II. 



particularly, as the dermal membrane is mostly wanting. Oscula and pores were not seen; the largest 

 fragment, which is of a longish form, may perhaps have had an osculum in one end, which then must 

 have been the upper end, an opening being found here leading into a long canal, but nothing can be 

 said with certainty as to this fact. 



The skeleton. The dermal skeletal/, as mentioned, consists of dermal spicules lying horizontally 

 in the dermal membrane, and the membrane is presumably supported in the common way by perpen- 

 dicular spicules. The main skeleton, as far as I have been able to examine it, consists of an irregular 

 network, partly polyspicular, partly, and for the greater part, unispicular; as in the two preceding 

 species, some longitudinal fibres are found here and there. In the nodes of the skeleton a very slight, 

 white, and clear mass of spongin is found. 



Spicula: a. Megasclera. i. The skeletal spicules are acanthostyli; they are comparatively 

 long and slender, somewhat curved, sometimes straight; the curve is most frequently nearest to the 

 upper end. The point is middle long or rather long. The spinulation may be somewhat varying, 

 from tolerably close to rather scattered, and there may also be some difference in the sizes of the 

 spines; the point is generally smooth for a shorter or longer space. A very characteristic feature 

 of the needle is that at its upper end some closer standing, larger spines may be found; 

 this feature may be more or less marked , but is almost never quite wanting. The length 

 is 0-298 — o-387 mra , the shortest forms are not frequent; the thickness is 0-0071— o-oi28 mm . The 

 specimen from the Kara Sea has comparatively shorter and thicker styli than that obtained by the 

 Ingolf. 2. The dermal s pic tries are tylota with rather slightly swollen, spined ends; they are 

 straight or very slightly curved, and cylindrical or slightly fusiform. As usual, there is a little differ- 

 ence between the two ends, one being a little thicker, the other a little thinner with a longer swelling; 

 in the thicker end the spines are most frequently only found at the very end, which is somewhat 

 abruptly cut off; the same feature may be seen in the thinner end, but here they extend most frequently 

 all over the swelling. The length is 0-25 — o-32 mm and the thickness 0-0055 — o-oo85' nm . b. Microsclera : 

 these are of only one form, anisochelse palmatse, bipocilla not being found. The chelae are of the 

 common type, the free part of the shaft is comparatively long, the tooth is of the same breadth and 

 the same, or about the same, length as the alee. They vary somewhat in size, the length is 0-017— 

 o-044 mm and the breadth 0-005 — o-oi5 m,n . 



This species is especially characterized by its rather long, slender styli with a few larger spines 

 at the head-end, and by the form of one or both ends of the tylota. The want of bipocilla is rather 

 interesting, and may also be regarded as a character of importance; but this fact alone would not be 

 sufficient for a characterization of the species, as the bipocilla seem to be present in very different 

 numbers in different individuals of the same Zop/iou-spec\es, and they may sometimes be found in very- 

 slight numbers. Levin sen 1. c. says that two sizes of the chela occur, but in reality all transitions 

 as to size are found. 



Locality: From the Ingolf territory we have only a small fragment obtained at East-Greenland, 

 at 72° 25' Lat. N., 19 33' Long. W., depth 140 fathoms (The East-Greenland Expedition 1891—92). 



Geogr. distr. Levinsen's specimen is from the Kara Sea, depth 73 fathoms. To judge from 

 these two localities, there is some reason to suppose the species to be a native of the cold bottom. 



