PORIFERA. II. 151 



always nearest to the rounded end; the point may be somewhat varying, but is upon the whole middle 

 long or rather long ; sometimes it is abruptly more shortly pointed at the very point itself. Their 

 length is 0-38— 0-62""", and the thickness is proportionately 0-012— o-02i mm The smaller sizes are little 

 frequent. Developmental forms occurred in small numbers, the finer ones were slightly rugged. 

 2. The dermal spicules are tornota; the}- are cyliudric and straight, or slightly, not rarely some- 

 what irregularly, curved; the ends are shortly and bluntly pointed with a little outer point marked off 

 especially. One end is always a little thicker than the other, and this latter is generally a little longer 

 pointed. Their length varies from 0327 — 07L58 min , and the thickness is ca. 0-006— 0"Oi mm . Very few finer 

 forms occurred, the thin ends of which were quite pointed, and accordingly they were styli. b. Micro- 

 sclera; these are two forms of pluridentate isaucoree spatuliferse, larger and smaller ones. 1. The 

 large ancorae are of a very beautiful form; the shaft is slightly curved, and they have at either 

 end five lanceolate teeth and a pair of narrow alse of about the same length as the teeth. The teeth 

 are placed in such a way, that a transverse section of the ancora through the teeth is about circular. 

 Ancorse with six or seven teeth, or with six or seven teeth at one end and five at the other end 

 occur singly. Not rarely the ancorse are a little twisted, so that the teeth of one end are situated 

 opposite to the intervals at the other end. Their length is 0-071 — 0-099""", and the thickness of the 

 shaft is 0-0057 — o-oo8o mm . Developmental forms of this ancora at all stages occurred frequently. The 

 youngest ones are quite fine, and look as if they had at either end a single, median, hook-like recurv- 

 ing, so that it might be supposed that the median tooth was the one first formed. By a closer exa- 

 mination, however, a couple of ridges are seen at the end of the shaft, which are surely beginning 

 teeth, but on account of the smallness and fineness of the parts it is a very difficult thing to get a 

 clear view of the exact structure of the end of the finest stages; soon after, in stages a little older, 

 all five teeth are seen as thin, plate-shaped outgrowths, so that it may more nearly be said that falxes 

 are first formed. 2. The small ancorse are also of a highly beautiful form; they have an almost 

 straight shaft, and seven to eight teeth and narrow alae at either end. The alae most frequently con- 

 tinue along the middle of the shaft as a narrow rim. The teeth are about parallel to each other and 

 to the shaft, and they are very close-standing; they are so long as to be only little removed from 

 each other in the middle. Most frequently the teeth are slightly curved, so that the ends are -directed 

 a little inward. The length is 0-0357 — o-048 m,n , and the thickness of the shaft is 0-0028— o-oo35 mm . The 

 large ancora occurs numerously, and in especially large numbers in the dermal membrane; the small 

 ancora, on the other hand, is far less abundantly present. 



Embryos. Some embryos were found scattered in the tissue; they are globular and of a size 

 of up to o-3'" m . In the sjjeeimens examined no spicules were found. 



Locality: Station 85, 63° 21' Lat. N., 25 s 21' Long. W., depth 170 fathoms; station 89, 64 45' Lat. N., 

 27 20' Long. W., depth 310 fathoms. Both stations are situated in the Denmark Strait. 



8. M. pluridentata n. sp. 



PI. V, Fig. 4. PI. XV, Fig. 3 a -e. 

 Cushion-shaped. The surface sliglitly shaggy. The dermal membrane thin, with penicillate bundles 

 0/ dermal spicules. The skeleton an irregular, polyspicular reticulation. Spicula: Megasclera: the skeletal 



