RADIATA. 863 
Europe, and was afterwards introduced into Spain and Africa, by the Arabs. 
In the time of the Crusades, the insect passed from the Morea into Sicily 
and Calabria. From Calabria, the ova and the mulberry were brought to 
France by some of the followers of Charles VIII., on his conquest of Naples, 
and the cultivation of this insect was afterwards encouraged and: patronized 
by Sully, as an important branch of national industry. ; 
The mode of feeding and managing the silk-worm, and procuring its deli- 
cate web, is detailed in numerous works both scientific and economical. 
The caterpillar feeds upon the leaves of the mulberry. After remaining in 
this state about six weeks, during which the caterpillar changes its skin four 
times, the animal ceases to feed, and begins to form an envelope or cocoon 
of silken fibres in some convenient spot, producing the minute threads, till it 
has formed an oval, yellow case or ball, abeut the size of a pigeon’s egg, in 
which it changes to a chrysalis. In this state it remains for about fifteen 
days, when the perfect insect is produced. This, however, is not allowed to 
happen when the animals are reared for the sake of the silk, from its being 
observed that the animal before leaving its cocoon, discharges a colored 
duid, which injures the quality. The cocoons are therefore exposed to such 
a degree of heat, as to kill the inclosed animals, a few only being saved to 
keep up the breed. 

The moth, when produced, is very short lived, breeding soon after the 
exclusion, and perishing after the deposition of the ova. The length of the 
silken tnread when unrolled, is said to be from three hundred to five hun- 
dred yards in length, and this thread is composed of two united threads, 
agglutinated together. 
DIVISION IV.—RADIATA. 
Tuts division of the animal kingdom comprehends a great number of be- 
ings, of organization more simple than the preceding classes. However 
different otherwise in their structure or form, they seem (according to Cuvier) 
to correspond, in the character of having all their parts disposed around a 
gommon axis, in two or more rays, or in two or more lines extending from 
ye extremity to the other. Even the intestinal worms have at least two 
