90 Dr. S. Lov^n on a remarkable Sponge. 



species of Hyalonema distinct both from H. Sieholdtj Grray, 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 Kroyer, which lives in the 

 North Sea, always far from the shore, bears a very close affi- 

 nity to the Japanese genus Galena of De Haan. 



Hyalonema may be traced far back in geological time. 



The sponge from the Greensand figured as Siphonia pyri- 



formis^ Goldf., by J. de C. Sowerby *, has a strong resemblance 



to it ; and Prof. Suess has recognized it in the Serpula paral- 



lela^ M^Coy, of the Yorkshire Coal-formation f. 



The genus Hyalonema may be characterized thus : — 



Hyalo>^ema, Gray. 



Spongia silicea ; corpus clavatum in facie superiore applanata 

 oscula gerens, stipite suffultum intrante, tereti, radiculis afSjso. 

 Spicula fusiformia stipitis ad longitudinem spiraliter et arte con- 

 juncta parenchymate tenui ; corporis in fasciculos radiantes congesta, 

 interstitiis parenchyma lacunosum amplum continentibus ; cuticulae 

 simplicia arcuata ; amphidisci [gemmulas vestientes ?]. 



1. Hyalonema Sieholdi, Gray. 

 Hab. in mari Japoniae. 



2. H. lusitanicum, Barboza du Bocage. 

 Hab. in mari Atlantico extra eras LusitanisB. 



3. H. boreaUf nob. 



Hab. in mari septentrionaH extra eras Norvegiae, profunditate 

 200 orgyarum. 



EXPLANATION OF PLATE VI. 



Fig. 1. Hyalonema boj'eale, nob., magnitudine sesquies aucta. 

 Fig. 2. Facias superior cum osculo. 

 Fig. 3. Facias externa strati dermalis. 

 Fig. 4. ]^adem, magnitudine auctiore. 

 Ftg. 5. Spiculorum ejusdem congeries. 



* Fitton, ' Strata below the Chalk,' p. 340, pi. 15 a. 

 t Verhandl. zool.-bot. Gesellschaft Wien, xii. p. 8o. (Ann. Nat. Hist, 

 ser. 3. xviii. 404.) 



