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, ab»ut 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 

 iluid, 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 thread 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. 



This 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 

 common axis, in two or more rays, or in two or more lines extending from 

 ine extremity to the other. Even the intestinal worms have at least two 



