26 
third time they are more or less pointed. 3°. In the oceurrence of 
roots. I have seen at Naples specimens grown on stones without 
any appearance of roots, but showing that they are-really present 
when the stone was cleft. 4°. In the shape of the spieules. Accor- 
ding to these facts to it seems to me the best way of determining 
our Sponge again as a variety of T. Iyncurium. 
The spicules found in this specimen are the following. 
1°. (tr°.) ac. f. [fig. 123, pl. IV] with more or less distinct head. 
2°. tr. tr. f. [fig. 126] with a little constriction beneath the 
head, in order to form transitions to (tr°.) tr. f. The obtuse ends 
seem to be characteristic for this variety. These and the preceding 
kind are very abundant. Both are varying in length; perhaps you 
may distinguish three kinds. 
3°. st. [fig. 124, pl. IV] The radii of the ordinary stellates are 
much shorter and thicker as in the type specimen of Tethya lyn- 
curium. But as Oscar Schmidt now considers his T. morum only 
as a variety of T. Iyncurium, so I think one is perfectly right in 
deelaring our obtusum again as a variety of T Iyncurium. They 
have not all the same diameter. 
4°, st. [fig. 125, pl. IV} The little stars with blunt-ended short 
radii are very numerous. They are much smaller than the prece- 
ding ones, as shows a comparison between figure 124 and 125. 
ll. Polymastia penicillus. (Mont.) Vosm. [Pl. I, fisg. 12 and 
13; pl. IV, figg. 127—132.] 
Diagn. Corpus uno latere planum, altero convexum; papillarum 
longarum multitudinem ferens. Spicula indicantia: tr°. ac. f | 
(tr°.)) aca (f).] 
Loeal. Lat. 72° HUN.; long. :37°57'E.; [Jak 25, 19782 
Geegr. distrib. Atlantie and Arctic Oceans; Mediterrenean. 
Depth. 140 Fathoms. 
Synon. and literature. 
1818. Spongia penicillus Mont. (acc. to Bwk.) 
(Montagu, Wern. Mem. pagg. 93—95; Tab. XIII, fig. 7.) 
