472 
NATURAL HISTORY OF AFRICA. 
solid matter of the globe. Zoophytes, from the sim- 
plicity of their structure, and the geognostic rela- 
tions of the rocks in which they are occasionally 
found, appear to have been called into existence 
before the other classes of animals. 
Of this numerous class of animals, many genera 
occur on the coasts of Africa. 
The Asterias, or star-fish, one of the most 
common of the zoophytic genera, is met with in 
many quarters. Of the species, one of the most 
beautiful and singular is that named Arborescent 
star-fish, (Asterias caput Medusae, Lin.) which is 
occasionally taken off the Cape of Good Hope. 
The celebrated Guinea- worm, (Filaria medinen- 
sie, Gm.) is very common in the warm regions of 
Africa, particularly Guinea. It insinuates itself 
under the skin of the human species, principally of 
the arms and legs, and there it attains the length 
of ten feet. It is said that it will remain there for 
several years without producing any disagreeable 
symptoms ; but it sometimes occasions violent pains, 
and even convulsion, according to the part of the 
body it attacks. When it begins to protrude itself, 
great care must be employed in extracting it, as 
it is very apt to tear and leave a portion behind, 
which occasions violent and disagreeable symptoms. 
The operation of extraction is one of some time. 
The Physalia, or Portuguese sailor, met with in 
