436 FRISTEDT, SPONGES. 
Genus Tethya Lmk. 
Tethya muricata Bow. 
Tethea muricata, Bow., Phil. Trans., Vol. 148, Part 2, pag. 308, Plate 25, fig. 18. 
Thenea muricata, Vosme&er, Niederländ. Archiv för Zoologie, Supplement- 
band I, pag. 5, Plate 1, fig. 1—8, Plate 2, fig. 1—21, Plate 
4, fig. 114—115. 
This species is represented by fine specimens, all obtained 
during the expedition to Greenland in the year 1883. They 
agree well with the description and the figures given by 
Vosmer. 
The largest specimen is of the size of a great hen-egg. 
Habitat. Baffin Bay, Lat. 75” 26' N., Long. 6T 27 W.> depua 
260 fathoms (542 5); Davis Strait, Lat 097033 No tioner 
25 W., depth 120 fathoms (576 S.); East-coast of Greenland, 
depth 150 fathoms (580 5). 
Tethya sibirica n. sp. 
Plate 24, fig. 22—28, Plate 28, fig. 17. 
Sponge ovoid or subspherical, furnished with numerous 
roots, by which it is attached to stones or other hard objects. 
The surface is slightly hispid from projecting spicules and armed 
with ridges or tubercles, which are joined in the upper part 
of the sponge. The consistency is tolerably firm. Sometimes 
the tubercles or ridges of the lower part are pointed to the 
roots; but then they are only undeveloped roots. Oscula few, 
rarely more than two, generally one of them is situated on 
the top of the sponge. The size of the sponge varies much. 
The smallest specimen is only as great as a hazel-nut. The 
largest is ovoid, the longer diameter being 90 mm, the shorter 
about 5 mm. This specimen is slightly compressed. The 
length of the roots varies from 5 to about 50 mm. One of the 
roots is usually larger than the others. 
Skeleton. The skeleton consists of long and short 
acerate spicules, of very slender porrecto- and recurvo-ternate 
spicules, and of sigmoid bihamate spicules. 
