38 



PORIFERA. II. 



peculiar way. Now it is not said whether spicules are found in these fibres, but they are figured 

 without such. A spongin skeleton of a so peculiar kind, not seen to be in any way connected with 

 the other skeleton, would be quite unique. By a look at fig. 24 it is obvious that the question cannot 

 be of spongin fibres; through the middle of each of the radiate fibres runs a line which is said to 

 mark the coalescing, but in reality shows that the figured things are evidently vegetable cells. As 

 before mentioned the sponge frequently grows round Algte, which is also the case with the figure of 

 the exterior given by Grentzenberg, and then the Alga runs about through the middle of the sponge; 

 the author also says that the peculiar circular fibre is found nearly in the middle of the sponge. To 

 be sure there can be no doubt that by the cutting out of the transverse section of the sponge the 

 incrusted Alga — it looks like a Polysiphonia -- has been cut through, and it is this transverse section 

 which has been interpreted as the peculiar circular fibre with the radiate fibres inside. 



The Espcria stolonifcra established by Merejkowsky 1. c. is by Levinsen referred to 

 ovuhim as a synonym, and to judge from the description and figures they are surely identical. I have, 

 however, in no case observed the net of thin off-shoots mentioned by Merejkowsky for some of 

 his specimens. 



Locality: Of this species we have a great number of specimens, all from Greenland, Iceland, 

 and the Faroe Islands. Greenland, without any designation of locality (Schmidt's type specimen) ; Egedes- 

 miude (M. Porsild); the Ingolf, off Bredebugt, on station 87, depth no fathoms; Rostin in Bredebugt 

 (H. Jonsson); Onundarfjord, depth 10 fathoms (the author); to the east of Bakkefjord, depth ca. 70 

 fathoms (Hallas); Skulavig in Seydisfjord, depths 6 fathoms and 30 fathoms; Berufjord, depth 10 fathoms 

 (A. C. Johansen); the Faroe Islands (Miiller); at the north point of Nolso, depth ca. 100 fathoms, 6 miles 

 N. to W. of Kalso, depth 60 fathoms, Saudsbugt (Th. Mortensen). 



Geogr. distr. Besides on the above localities the species has been taken in the Cattegat between 

 Samso and Sealand (L-evinsen 1. a); in Great Belt, depth 24 fathoms, and in the Baltic at Kiel, depth 

 3—6 fathoms, Darserort, depth 15V2 fathoms, Stoller bank, depth 3—5 fathoms (Schmidt, 1873), further 

 at Bergen and Espevser (Arnesen), finally in the White Sea (Merejkowsky). 



Note. Three of the My calf -species mentioned in the literature, are with rather great pro- 

 bability to be referred to the present species; I do not, however, venture to decide this question with 

 certainty, or to make any change of names on that account. The first of these species is M. (Isodictya) 

 lobata Bow. (M011. Brit. Spong. II, 326, III, 148, PI. LVIII, figs. 19—22); Bowerbank, to be sure, men- 

 tions «bihamates , which are not figured; but these needles might very well be developmental forms 

 of the cheke, and such a fact might also be implied by the observation that they are «exter-umbonates . 

 The second species is M. (Isodictya) Clarkci Bow. (1. c. II, 330, III, 142, PI. LVI, figs. 11— 15); the figure 

 of the exterior of this species, which grows on Hydroids, is quite similar to longish specimens of M. ovu- 

 lum. Topsent, in his list (Rev. biol. du Nord de la Fr. VII, 15 and 20) has taken this species to be 

 an Espcriopsis, and has referred it as a synonym to E./uconini Johnst. Bowerbank, however, calls 

 the chela « inequi-an eh orate , and the figure also shows an anisochela, but, to be sure, an anisochela 

 in which there is onlv little difference between the two ends, such as occur in M. ovulum. The third 

 species is the E. modesta established by Lambe (Transact, of Roy. Soc. of Canada XII, 1894, Sect. 4, 



