156 



PORIFERA. II. 



wrong impression of the alse, as well in this as in many other arcuate chelae, if it is not sufficiently 

 magnified; the fact is that only the foremost, refolded edge is seen distinctly, and the ala seems to be 

 more or less claw-shaped. When, on the other hand, the magnifying powers are sufficiently high, the 

 contour of the ala is seen distinctly, as given in Fig. 4 c, PI. XV. The length of the chela is 0-038— 

 o-044 mm , and the thickness of the shaft is 0-0024— o-oo50 mm ; this variation of the thickness of the shaft 

 is most dependent on the way in which the chela is seen, from the front or from the side, as the shaft 

 is not cylindric, but rather much compressed. Developmental forms in different stages were seen in 

 small numbers. 



Locality: Station 10, 64 24' Lat. N., 28 50' Long. W., depth 788 fathoms, a fragment; station 27, 

 64 54' Lat. N., 55 10' Long. W., depth 393 fathoms, two specimens and a fragment. The stations are 

 situated in the Denmark Strait and in the Davis Strait. 



2. L. Sophia Frstdt. 

 PL V, Fig. 6. PL XV, Fig. 5. 



1887. Esperia Sophia Fristedt, Vega Exp. vetensk. Iakttag. IV, 451, PL 25, figs. 30—32. 



Erect, leaf-shaped. The surface smooth. The dermal membrane a thin film, on the pore side 

 supported by pillars of dermal spicules, but here without horizontal spicules, while on the oscular side it 

 has only horizontal spicules. Oscula and pores each on their own side. The skeleton diffuse and quite, 

 irregular, formed by single spicules and loose bundles. Spicula : Megasclcra : the skeletal spicules acan- 

 thostyli 0-44 — 0-518""", the dermal spicules strongyla with finely spincd, sometimes smooth ends, o-2j — 

 0-J4"""; microsclera of one form, chela' arcuatce 0-028 — o-oj^""". 



We have two somewhat damaged specimens of this species; both of them are erect and leaf- 

 shaped; one specimen is seen to have been attached by its lower edge, which shows a surface of 

 attachment; this surface occupies almost the whole breadth of the leaf, so that the sponge has not 

 been narrowed to a stalk. Fristedt says of the species that it is «massive, probably thickly incrust- 

 ing hard objects». Whether the question is here of the sponge forming below a basal expansion, or 

 Fristedt has made a mistake in his interpretation, I am not able to decide. The largest of my 

 specimens is 50 mm high, 8o mm broad, and ca. n mm thick. The consistency is middle hard and little 

 elastic. The colour (in spirit) is dirtily brown. The surface is smooth, without projecting spicules. The 

 dermal membrane is a thin, transparent film, supported by pillars of dermal spicules which do not 

 project through it, or only to a very slight degree; on the pore side it is otherwise without spicules, 

 while on the oscular side it has horizontal spicules. Pores and oscula belong each to their own side; 

 the pores are closely gathered, so that the membrane gets a sieve-like appearance; they are generally 

 of a circular form, and were measured of sizes from 0-035 — o-i5 mm . Pores may also be found on the 

 oscular side. Oscula are found scattered and in rather small numbers on the opposite surface; they 

 are only to be seen with difficulty, as the opening itself is not seen; the fact is that the membrane 

 forms a quite low and almost not at all projecting spout or cone, at the top of which the lobate 

 aperture is found. While the horizontal spicules of the membrane otherwise are scattered on the 



