PORIFERA. II. 183 



to reach their climax in the figures of the spicula of this species. Also of Fristedt's Esperia Patter- 

 soni I have examined one of the author's specimens, and have found his species to be identical with 

 dubius, only the spicules are a little more spined than in my specimens. How the relation is between 

 this species and those of Bower bank, I cannot say with certainty; the question can only be of the 

 two species nigricans and Pattersoni. Of Pattersoni I have examined a specimen sent me by the Rev. 

 Mr. Norman; according to this specimen, this species seems to have thinner styli, they did not exceed 

 Q.QQg.nm j n thickness Bowerbank figures the dermal spicules as spined all over, but in the description 

 he says terminally spined ; in the specimen I have examined only the ends were spined. /.nigricans 

 I have not seen; the style figured by Bowerbank does not show the spines more closely gathered 

 at the upper end, but this feature is not always distinctly marked in dubius either. None of the two 

 sptcies, on the other hand, seems to have the characteristic exterior so frequent in dubius. Topsent 

 (Rev. biol. du Nord de la Fr. VII, 19) unites Bowerbank's two species, which is perhaps correct; 

 neither is it precluded that the present species may prove to be identical with them ; this question 

 can only be decided by a close examination of all Bowerbank's specimens, and for the present 

 dubius must be kept up. 



Locality: We have a very great number of the species, but only from the sea round the Faroe 

 Islands, where it must be very commonly found, and southeast of Iceland. At the north end of Nolso, 

 depth ca. 100 fathoms; six miles northwest of Kalso, depth 60 fathoms; thirteen miles northwest of 

 Boronass, depth 30 fathoms (Th. Mortensen); 64° 27' Lat. N., 13 27' Long.W., depth 84 fathoms (Ad. Jensen, 

 the cruise of the Michael Sars» 1902). 



Gcogr. distr. Between Spitzbergeu and Norway, at 72 27' Lat. N., 35° 01' Long. E., depth 136 

 fathoms (The Norwegian North-Atlantic Exp.); the Vaigat Islands at Spitzbergeu, depth 60 fathoms 

 (Fristedt I.e.). The species seems to be a native of rather shallow water, its bathymetrical range being 

 30 — 136 fathoms. For the locality from the Norwegian North-Atlantic Expedition is stated a bottom 

 temperature of o° C. 



3. I. frigidus n. sp. 

 PI. XVII, Fig. 5 a- f. 



18S6. Esperella picea Levinsen, Dijmphna-Togtets zool.-bot. Udbytte, 360, Tab. XXXI, figs. 1, 2 a— d. 



Form ? The dermal membrane a thin film luith a reticulation of dermal spicules. The skeleton 

 an irregular, for a great part uuispicular, network. Spicula: Megasclera: the skeletal spicules acantho- 

 s/yli with some close-set. large spines at the head-end, o-2g8 — o'j8?'" m ; the dermal spicules tylota with 

 spined ends 0-23 — -j 2 """; microsclcra of one form, anisochelce palmata of the Iophon-typc croiy — 0-044""". 



Of this species we have from the Ingolf-territory only one very small fragment, and so I am 

 obliged to use Leviusen's specimen for the description; also this specimen, however, is so badly 

 preserved, that the description must chiefly be restricted to the spicules. From the Kara Sea we have 

 some fragments (Levinsen's specimen), which have presumably belonged to one sponge. The largest 

 one of these fragments has a greatest extent of 70""". The consistency in the present state is loose 

 and soft, and the colour (in spirit) is brown, not especially dark. A thin dermal membrane is found 

 with horizontal spicules, forming a net, but it has not been possible to examine the structure more 



