124 Dr Grant's Observations cm the Structure 



bable, that, by removing the spicula, we might obtain from the 

 earthy sponges of our own coasts the advantages for economical 

 use derived from the elastic species of tropical seas. The soft 

 gelatinous matter mentioned above, as escaping abundantly from 

 the broken S. panicea, is met with in greater or less quantity in 

 all the other species which have been examined. Cavolini ob- 

 served it to be very abundant and consistent in the S. officinalis 

 and *S'. carnosa. Schweigger observed it to be most abundant in 

 the sponges of the Mediterranean in autumn. Vio and Olivi 

 considered it as a distinct matter from the other soft parts of the 

 sponge; and Schweigger found it to consist almost entirely of 

 minute granules, with a little transparent moisture. It has an 

 unctuous feel, emits a fishy odour when burnt, leaves a thin film 

 or membrane when evaporated, and appears to the naked eye 

 transparent, colourless, and homogeneous, like the colourless part 

 of an egg. But, when a drop of it is examined on a plate of 

 glass under the microscope, it appears entirely composed of very 

 minute, transparent, spherical or ovate granules, Kke monades, 

 with some moisture. These monade-like bodies, nearly all of the 

 same size and form, resemble the pellucid granules or vesicles, 

 which Trembly has represented as composing the whole texture of 

 the hydrae, or the soft granular matter we observe in the stems of 

 living sertulariae, and, indeed, most of the fleshy parts of orga- 

 nised bodies appear to be composed of similar pellucid granular 

 or monade-like bodies in different states of aggregation. This 

 soft substance, which might be termed the parenchymatous mat- 

 ter of the sponge, to distinguish it from the tough connecting 

 matter of the spicula, is found in all parts of the body, but is 

 chiefly contained in the intermediate spaces between the parietes 

 of the internal canals, and it is more abundant at the time when 

 the ova first make their appearance. The tough glistening sub- 

 stance which lines the internal canals, and passes over the sur- 

 face, between the pores, is the most highly organized part of 

 the animal. That of the canals resists repeated strong agitation 

 in fresh water, and appears through the microscope a very con- 

 sistent homogeneous jelly, with a rough granulated internal sur- 

 face. The roughness sometimes assumes a lineal appearance, 

 exhibiting the rudiments of fibres, and the transparent granules 

 which project considerably from its surface, become more rare 



