52 OPINIONS AND DISCOVERIES 



runs down like the white of an egg when the sponge is first 

 torn from the rock, and suspended between the fingers ; 

 the microscope detects no trace of organization in it ; by 

 fining up the inequalities of the sides of the tubes, it 

 smoothens these passages for the small streams. Every 

 part of the gelatinous matter is covered with minute gra- 

 nular bodies, which are distinctly seen in every species of 

 sponge by the weakest magnifier of the microscope. These 

 granular bodies are represented in the plates of Donati, of 

 a spherical form, adhering to the quadriradial fibres of 

 what he has named the Alcyonium primum Dioscoridis. 

 They are quite invisible to the naked eye ; they escape 

 along with the gelatinous matter, and compose the greater 

 part of it ; they are connected with each other by the ge- 

 latinous matter, and probably through the same medium 

 have some connection with the spicula along which they 

 are placed. No part in the organization of the sponge is 

 more constant and obvious than these granular trans- 

 parent bodies, lining the interior of every canal fi-om the 

 pores to the fecal orifices. Their form is not quite sphe- 

 rical, but somewhat lengthened or ovoidal, and they are al- 

 ways attached by one extremity to the gelatinous matter, 

 while their opposite end is seen to project free into the ca- 

 vity of the canals. Through the greatest magnifier of the 

 microscope, no difference can be detected in their forms 

 in different species of sponge ; they all appear to be en- 

 larged and rounded at their free projecting extremity, 

 and when watched with attention, we distinctly perceive 

 that they possess some power of spontaneous motion, both 

 when in connection with the sides of the canals, and when 

 lying isolated at the bottom of the water. The ova of the 



