64 CLASS CONCHIFER.A.. 



power of cattin<? or bieakinj; them off. The liquid 

 matter, out of which they are formed, is so exeeeJino-ly 

 glutinous as to attach itself firmly to the smoothest 

 bodies. It is hut slowly produced, for it appears that no 

 Pinna is capable of formino: more than four, or at most 

 five threads, in the course of a day and night. The 

 breads which are formed in haste, when the animal is 

 disturbed in its operations, are more slender than those 

 which are constructed at its leisure. In Sicily, and 

 other parts of the Mediterranean, these threads have 

 been manufactured into gloves, and other articles, which 

 resemble silk. 



The number of muscles by wliich the shells are moved 

 have caused tliis Class to be divided into two orders: the 

 Bimusculosa, in which there are two pair of muscles to 

 perform this office; and the Unimusculosa, with only one 

 nair. 



ORDER UNTMUSCULOSA. 



The Conchiforous animals which possess but one pair of 

 muscles, are much more limited in number than those 

 which possess two or more; hut they contain in their 

 ranks several well-known and useful species, as, for 

 instance, the oyster, the mussel, and the animal which 

 produces the oriental pearl. 



The Horse- Foot Bowl Shell, 

 ( A nom ia epit ippium.) 



The shells of the Anomice are exceedingly irregular in 

 their form ; like the oysters, they remain during the 

 whole of their existence attached to one spot, either on 

 a rock, or on the shell of some larger inhabitant of the 



