3 35 
and Functions of the Sponge . 
rock. They are doomed to have but one free surface for the 
distribution both of their pores and fecal orifices ; and, therefore, 
the pores, and the narrow tubes leading in from them, must 
either pass on separately through the body, and open again, 
each by a distinct orifice on the surface, or they must pour their 
currents into certain general reservoirs or canals, ramified through 
every part of the body, which may convey them away by few 
and large orifices. In the former case, there would be as many 
fecal orifices pouring their foul contents over the downy surface 
of the animal, as there are pores whose delicate inhabitants are 
struggling to convey a limpid stream through the interior. In 
the latter case, which is the arrangement followed by nature in 
the construction of this beautiful and complicated zoophyte, a 
much greater surface is allowed for the distribution of the pores, 
and much greater cleanliness is observed in discharging the fecu- 
lent matter, by a few orifices, and those placed at a convenient 
distance from the pores. The branched sponges, as the oculata , 
dichotoma , &c. are, in this particular, placed nearly in the same 
circumstances as those which spread over the surface of rocks : 
they have but one surface for the distribution of their pores and 
fecal orifices, and, consequently, we observe them collect their 
currents, and bring them back to the surface, by few and large 
orifices, which are conveniently arranged along the outer mar- 
gins of the branches. Every sponge, therefore, possesses fecal 
orifices, though differing remarkably in size and distribution in 
the different species ; and though the following observations and 
experiments have been made chiefly on those orifices which are 
large and conspicuous, and have already been observed by na- 
turalists, it is evident that they must apply equally to those 
which have escaped observation from their minuteness. 
Since Marsigli first stated, more than a century ago, that he 
had actually seen these round fecal orifices on the surface con- 
tract and dilate themselves in the sponges of the Mediterranean, 
Ellis and Dr Knight have declared the same fact respecting the 
sponges of the English coast, and the same statement has been 
repeated by other naturalists. Solander, Ellis, Gmelin, Bru- 
guiere, and Bose, have introduced the singular power of suction 
ascribed to the fecal orifices into their definitions of the sponge. 
Lamouroux and Lamarck consider these orifices as destined to 
