90 Dr. 8. Lovén on a remarkable Sponge. 
species of Hyalonema distinct both from H. Steboldi, Gray, and 
from H. lusitanicum, Barboza du Bocage. In the present state 
of our knowledge of sponges, it is not advisable to make a new 
genus of it. 
There exist between the fauna of lower animals living in 
the North Sea or fossil in the Crag formation, on one side, 
and that of the Japan seas, on the other, certain analogies 
which deserve to be kept in view. The crustacean Geryon 
tridens, for instance, described by Kréyer, which lives in the 
North Sea, always far from the shore, bears a very close afti- 
nity to the Japanese genus G‘a/ena of De Haan. 
Hyalonema may be traced far back in geological time. 
The sponge from the Greensand figured as Stphonia pyri- 
formis, Goldf., by J. de C. Sowerby*, has a strong resemblance 
to it; and Prof. Suess has recognized it in the Serpula pqral- 
lela, M‘Coy, of the Yorkshire Coal-formation f. 
The genus Hyalonema may be characterized thus :— 
Hyatonema, Gray. 
Spongia silicea; corpus clavatum in facie superiore applanata 
oscula gerens, stipite suffultum intrante, tereti, radiculis affixo. 
Spicula fusiformia stipitis ad longitudinem spiraliter et arte con- 
juncta parenchymate tenui ; corporis in fasciculos radiantes congesta, 
interstitiis parenchyma lacunosum amplum continentibus ; cuticulee 
simplicia arcuata ; amphidisci {[gemmulas vestientes ? ]. 
1. Hyalonema Sieboldi, Gray. 
Hab. in mari Japonie. 
2. H. lusitanicum, Barboza du Bocage. 
Hab. in mari Atlantico extra oras Lusitanie. 
3. H. boreale, nob. 
Hab. in mari septentrionali extra oras Norvegie, profunditate 
200 orgyarum. 
EXPLANATION OF PLATE VI. 
Fig. 1. Hyalonema boreale, nob., magnitudine sesquies aucta. 
Fig. 2. Facies superior cum osculo. 
Fig. 3. Facies externa strati dermalis. 
Fig. 4. Eadem, magnitudine auctiore. 
Fig. 5. Spiculorum ejusdem congeries. 
* Fitton, ‘Strata below the Chalk,’ p. 340, pl. 15 a. 
+ Verhandl. zool.-bot. Gesellschaft Wien, xii. p. 85. (Ann. Nat. Hist. 
ser. 3. xviii. 404.) 
