406 3Ir. Hogg's Observations on the Spongilla fluviatilis, 



I think they really present a stronger affinity with many of the Fioigi, par- 

 ticularly with the more permanent and porous kinds, several of the Bolet'i and 

 Polypoii, for instance ; I therefore propose to classify them as follows. 



Natural System. 



Class III. ACOTYLEDONES. 



Division I. Terrestres. 



Nat. Ord. Fungi. 



Division II. Aquatice. 



Sen Hydrophyta et Thalassiophyta. 



Nat. Ord. Spongle. 



Spongiarum genera ; ac Spongilla. 



Nat. Ord. Alg.e. 



Linnean System. 

 Class XXIV. CRYPTOGAMIA. 



Ord. 4. Alg/e. 



Ord. 5. Spongi.î;. 



Spongilla, et Spongiarum genera Marinariim. 



Ord. 6. Fungi. 



Or, indeed, if it be thought upon the whole more advisable and more con- 

 sistent with the nature of their structures that all the Sponges be included in 

 the heterogeneous order Alga^, they should then compose a distinct and sepa- 

 rate family, Spongiacecc, and be placed immediately next to the order Fungi. 



Notwithstanding that our knowledge respecting the nature of Sponges has 

 during the last fifteen years i-eceived some advancement, I must express a 

 liope to you that observers, whose leisure and situation on the sea coast* afford 



* The difficulty of preserving Sponges, even in bottles filled with rectified spirit of wine, is so great, 

 that no one, who has not the means of examining them in a fresh condition and in their native element, 

 can ever expect to throw much light on their variously-formed structures. The dried masses of fibrous 

 skeletons, devoid of their true natural forms and colours, without their parenchymatous jelly and en- 

 veloping membrane, &c., as exhibited in our museums, can but little assist us in obtaining a correct 

 knowledge of their natural history. 



