2i6 POR1FERA. II. 



form, their length is 0'02i — o-028 mm , and the breadth is ca o-ooj" 1 ™. The three forms of microsclera are 

 found through the whole sponge; in the dermal membrane the small aneora may be seen, and on the 

 lower side of this membrane the sphaerancorae are found; in the pore sieves the sphaerancorae and the 

 small ancorae are of frequent occurrence, while the large ancorae are scarce. The sphaerancorae are 

 frequently, but not always, seen in the membranes of the canals in large numbers; they are placed 

 perpendicularly with one end towards the lumen of the canal, and between them both forms of the 

 ancorae are seen. The sphaerancorae and the small ancorae are upon the whole most frequent, while 

 the large ancorae are present in far smaller numbers. 



In this species «cellules spheruleuses* occur so abundantly, that the tissue seems almost 

 exclusively to be formed by them ; they are roundish or irregular, filled with rather large, clear, some- 

 what refracting granules. Their average size is ca. o-oi7 ram . They are seen in large numbers in the 

 dermal membrane and especially in the canals of the membranes. 



Locality: Station 78, 6o°37' Lat. N., 2f*p! Long. W., depth 799 fathoms; station 81, 6i°44' Lat. N., 

 27°oo' Long. W., depth 485 fathoms; station 90, 64°45' Lat. N., 29°o6' Long. W., depth 568 fathoms; further 

 it has been taken at the Faroe Islands, southwest of Myggenaes, depth 135 fathoms (Ditlevsen); north 

 of Iceland, depth 58 fathoms (H. M. S. «Beskytteren», Gemzoe), and at 62°29' Lat. N., 5 17' Long. W, depth 

 190 fathoms (Ad. Jensen, the cruise of the Michael Sars» 1902). Six specimens in all. The localities 

 are situated in the Denmark Strait, north and southwest of Iceland, and at the Faroe Islands. 



Geogr. distr. The species seems to be very widely distributed; it has hitherto been obtained 

 between Scotland and the Faroe Islands (the « Porcupine ), Reksten Fjord, depth 200— 300 fathoms (the 

 «Argo»), Bergen, 53 — 96 fathoms (Arnesen I.e.), the eastern coast of Greenland, depth 130 fathoms (Fri- 

 stedt 1. a), in the Caribbean Sea (Schmidt 1. a), and at New Foundland, depth 673 fathoms, and the 

 Azores, depths from 278 — 724 fathoms (Topsent I.e.). 



2. M. emphysema O. Schmidt 

 PI. XX, Fig. 2 a— d. 



1875. Desmacidon emphysema O. Schmidt, Jahresber. der Comm. zur wissenschaft. Unters. der deutsch. 



Meere in Kiel, fiir 1872—73, 1875, T1 ^- 

 1885. ? Melonanchora elliptica Vosmaer, Bijdrag tot de Dierk., 12. Afl., 3. Gedeelt, 31, PI. I, figs. 14 et 22, 



PL IV, figs. 23-34, PI. V, figs. 69-72. 

 1903. Melonanchora emphysema Thiele, Archiv fiir Naturgesch. Jahrg. 1903, I, 392. 



Incrusting or massive. The surface set with wart-shaped pore papillce, otherwise smooth. The 

 dermal membrane solid, zuith close-lying horizontal spicules, supported by perpendicular fibres. Oscula 

 scattered, spout-shaped. The skeleton chiefly polyspicular, consisting 0/ fibres passing towards the surface 

 and sparsely connected by scattered spicules. Spicula: Megasclera of one form only, uniform throughout 

 the skeleton ; they are tylota with transitions to strongyla 0-44 — o m 6i mm ; microsclera of three forms, 

 spha'rancora 0-050 — 0-056""", aneora spahriifera of two forms, large ones o-o$j — o-o/S'""", small ones 

 0-024 — 0-030""". 



