PORIFERA. I. ,1 



from South-Australia; the spicules of this species are said by Carter to divide into two groups of a length 

 of respectively o-i— 0-13""" and o-358™'", and a thickness of 0-006'""; these measures, as we have seen, 

 agree very well with those of the spicules of the present species; the only difference is that the spi- 

 cules are said to divide into two groups, of which the smaller one should be chiefly found in the skin, 

 while in the present species spictiles of all intervening sizes are found, and the smaller ones sure 

 enough may be found in the skin, but are not chiefly found there. Dendy describes the skin as 



provided with a dense feltwork of oxea«, that may be arranged in a netlike manner on account 



of the pores, that is to say, a structure quite resembling tliat of the present species, with which, more- 

 over, the description agrees exactly. When Dendy 1. c. supposes //. nigrociifis to be allied with cer- 

 tain of the Sicllettinopsis-a^Qcies described by Carter, it seems to me to be quite justified, which is 

 also the case with regard to the present species')- On the other hand the species seems to be allied 

 to Halichoiidria colossta and the species most closely allied to this latter one. Therefore the possibility 

 of a relationship between HaUcho)idria and the Tetractinellids through Halichondria-StrUettinopsis 

 (Coppatias Sollas), suppo.sed by Sol las (Challeng. Report, Vol. XXV, Tetractinellida, 208), as also men- 

 tioned by Dendy, I.e., might be of some probability. 



Eumastia O. Schmidt. 



Front ail nftaclird. f/iiiiitrr or thicker basal part comparatively slender papilhr rise. The skeleton 

 consists of loose, irregular fibres and spread needles. The needles slender, long tapering oxea. 



I. E. sitiens O. Schmidt. 



PI. IV, Figs. I — 6. PI. X, Figs. 9 — 12. 



1870. Eumastia sitiens O.Schmidt, Grundziige einer Spongienf. des atlant GebieL 42, PI. V, fig. 12. 



1887. — — Fristedt, Vega Exp. vetensk. lakttag. IV, 426, PL 24, fig. 13, PI. 27, fig. 11. 



1896. — — Lambe, Sponges from the Atlant. Coast of Canada. Transact. Roy. Soc. Canada, 



Ser. 2, II, Sect. IV, 182, PI. I, fig. i. 



The form different, often more or less irregular. From the attached basis rise close-standing, 

 slender, nnbranched or slightly branched papillce, some of 7vhich bear oscula. Tlie surface smooth. The 

 dermal membrane is on the papillcE provided with a reticulation of spicules. 'The skeleton consists of 

 loose fibres and numerous spread spictiles. Spicula slender, long tapering oxea ca. o-j6 — /""". 



This species has a rather constant form; the nethermost part is expanded on the substratum, 

 and from this part slender, close-standing papillae rise. In its most regular form it is of almost equal 

 extent in all direction.s, but it ma\- also be more expanded and become somewhat more irregular, and 

 the comparative development of the lower part and the papillae ma>' also be somewhat different. The 

 largest specimen has a largest extent of ca. 15'='". The other specimens vary in .size from ca. 2^1 f" to 

 ca. 7'=". All the specimens have been attached; the largest one has grown round the stalk and root 

 of a Laminaria; most of the others are either attached to shells of Pecten and living specimens of 

 Pecten (Pecten islandicus Miill.) or on Balanoids; a single one is attached to an old anchor. The 



I) By the boiling of the spicules of this species, I have in several instances found asters; I regard it, however, to be 

 quite sure, that these asters that have only been found quite singly, are extraneous bodies. 



