PORIFERA. I. 43 



is of no frequent occurrence; the length occurring most frequently, is o-agS"""; the thickness varies from 

 O'Oi — 0-014™™. 



Locality: Station 138, 63" 26' Lat.N., 7"" 56' Long. W., depth 471 fathoms, one fragment. The bottom- 

 temperature on this station was below zero, viz. — o'-6 



6. R. clavata Levinsen? 

 PI. XI, Fig. 9. 

 1886. Renicra clavata Levinsen, Dijmphna Togtets zool. bot. Udbytte 351, 10, Tab. XXIX, fig. 5, 

 Tab. XXX, fig. 3. 



There are in the collection two small, lengthily pyriform specimens, one having a length of 

 27""", the other of 19™™. With regard to their appearance, outer structure, and skeleton they seem to 

 agree very well with R. clavata\ I am, however, inclined to regard the determination as doubtful, be- 

 cause the spicules have an average length of 0-29™™, and a thickness of 0-014 — 0-015""", while in clavata 

 the length of the spicules is most frequently ca. 0-23""", and rarely reaches 0-26""°; the thickness is the 

 same. Otherwise the skeleton is of the same structure, being regularly unispicular, and consisting of 

 primary fibres, radiating arcuately upward and outward towards the surface, and connected by trans- 

 verse fibres; besides some thicker, polyspicular fibres are found branching from the stalk up into 

 the sponge. 



Localifv: East-Greenland, 72" 40' Lat. N., ca. 20° Long. W., depth 100 fathoms, two specimens 

 (The East-Greenland expedition 1891 — 92). 



Gcogr. distr. Rcniera clavata is known in one specimen from the Kara Sea from a depth of 

 74 fathoms. 



Vanhoffen (Gronl. Exp. d. Gesellsch. fiir Erdkunde zu Berlin, II, i. 1897, 248) enumerates 

 R. clavata from Karajakfjord, North-Greenland. I have had occasion to examine the spicules of the 

 species; thev have an average length of 0-22'"", and the thickness is o-oi2 — 0-014™™; thus the spicules 

 are a little thinner than in the original; the skeleton is a unispicular network. Without a closer 

 examination it is impossible to decide whether the species is really clavata, but it seems rather pro- 

 bable. Vanhoffen thinks A', clavata and R. simplex Arm. Han.s. to be identical; this, however, is 

 not the case, as will appear later under R. voeringii milii = R. simplex Arm. Hans. 



7. R. cinerea Grant. 

 PI. XI, Fig. 10. 

 1827. Sp07igia cinerea Grant, Edinb. New Philos. Journ. II, 204. 



1842. Halichondria cinerea Johnston, Brit. Spong. and Lithophytes no, PI. IV, fig. 4. 

 1866. Isodictya cinerea Bowerbank, Mon. Brit. Spongiadse II, 241, i, III, PI. XLVIII, figs. 1—5. 

 1870. Renicra cinerea O. Schmidt, Spongienf. Atlant. Gebiet 77. 

 1885. — — Fristedt, Kgl. Svensk. Vet Akad. Handl. B. 21, Nr. 6, 26. 



J887. — — Fristedt, Vega Exp. vetensk. lakttag. IV, 419. 



1887. — — Ridley and Dendy, Challeng. Report, Monaxonida, Vol. XX, 15. 



Of this species we have some dried specimens, all growing on a branched Lithothamnion; they 

 are cushion-shaped, more or less roundish, and in their dried state of a light yellow colour, a few of 



6* 



