126 TOILERS IN THE SEA. 



neighbours, unite together, forming a complex net- 

 work, which presents a remarkable resemblance to 

 ganglionic corpuscles. It is undoubtedly through 

 the stimulus received and transmitted by them that 

 the characteristic contraction and expansion of the 

 pores, or oscula, and other portions of the sponge 

 body, are accomplished." 1 The relations between 

 these amoeboid bodies and the flagellate monads is at 

 present little more than conjecture ; but Mr. Kent 

 does not regard the former as independent structures, 

 but rather as larval, or metamorphosed, phases of the 

 collar-bearing monads, it having been clearly observed 

 that the latter, when their course is run, lose their 

 collar and flagellum, and become amoeboid. 



This endeavour to explain, as briefly as possible, 

 the economy of what may be termed the sarcodous, 

 or fleshy portion of sponge structure, has been neces- 

 sary in order to exhibit the complexity of what at 

 one time was considered a very simple matter, and 

 dismissed with little more than an intimation that it 

 was called " sarcode," and was the amorphous flesh 

 of the sponge. Even now there is undoubtedly 

 much more to be known, and further investigation, 

 proceeding as rapidly as during the past few years, 

 will elucidate that which is still dark and uncertain. 

 If, in each individual sponge, we should come to 



1 Kent's "Manual of the Infusoria," p. 172. 



