SPONGES. 191 



As we view the Officinal Sponge, it is nothing but a resilient, horny 

 tissue, which admirably sexwes the purposes to which it is generally applied, 

 and, looking at it apart from all other connections, we might be inclined 

 to think that it is a product of the earth specially intended for the use of 

 man and nothing else ; but knowing now that there are no " hard and 

 fast linos" in creation, wherein all things are united by gradationary 

 transition, so as to produce universal harmony and one great whole, we 

 are irresistibly attracted by this view to consider the connections of the 

 Officinal Sponge, and when we find that it is actually the skeleton or organ 

 of support of a once living being, whose varieties are spread over the 

 earth almost as plentifully as plants, we not only become equally desirous of 

 knowing what these are, but of interpreting thereby the real nature and 

 position of the typical sponge through its varietal transition into the 

 other and better known spheres of development of the animal kingdom 

 which surround it. 



Having stated that the Officinal Sponge is an animal product, it will 

 be my business presently to prove this, merely premising now that 

 although very low in our scale of creation, it is a long way on the animal 

 side of the imaginary line of demarcation which separates tbe animal 

 from the vegetable kingdoms, so that it is absolutely an animal as much 

 as that which produces the coral. 



A sponge, then, may be defined to be a congeries of living beings 

 •which, like the coral, produces various kinds of structure in accordance 

 with the species ; of which the Officinal Sponge is one that comes into 

 the market for sale also like the coral, viz., devoid of the soft or more 

 animal parts which produce it. But as all kinds of sponges do not 

 produce an almost imperishable skeletal structure like that of the 

 Officinal Sponge it is desirable to state that (using the term " Spongida" 

 for the whole class) it may be divided into eight orders, as follows : — 



Ord. I., Carnosa. — These sponges have no imperishable skeleton or 

 organ of support, and substantially present to the unassisted eye nothing 

 but a gelatinous or semi-cartilaginous mass, charged or not with spicules 

 according to the family to which they belong. 



Ord. II., Ceratina. — In these there is a comparatively imperishable 

 skeleton, composed of horny fibre cored throughout by an axial canal, 

 which, in the fresh state, is filled with a soft granular substance that, on 

 drying, is replaced by a hollow cavity. 



Ord. III., Psammonemata. — Here there is not only a horny, fibrous 

 skeleton, with a more or less granular axis in the fibre, but this for the 

 most part is filled with foreign material, such as particles of sand, frag- 

 ments of sponge-spicules, and the like minute bodies, drawn in from 

 the exterior, and, therefore, arranged in position by the sponge previous 

 to its becoming the axis of the horny filament. 



Ord. IV., Rhaphidonemata. — In these, the horny, fibrous skeleton is 

 well developed and very resilient, but the fibre is axiated by spicules, 

 (siliceous bodies of different kinds varying in form with the species,) 



