14 THE ELEMENTS 



the base is fixed, and G a piece of 

 wood to which the shells of this sec- 

 tion are generally affixed. 



Ligament is the substance by which 

 the valves or parts of the shell are 

 connected. Some multivalve shells 

 are connected, by the parts of one 

 valve looking into another. Plate 1st, 

 fig. 2d, DDD. 



Ridges are those cavities in many 

 of the lepas tribe, sometimes lon- 

 gitudinal and sometimes transverse. 

 Plate 1st, fig. 1st, FF. 



Peduncle. A sort of stem by which 

 the shells of the second division of 

 lepas are attached to wood, &c. It is 

 a kind of membranaceous substance, 

 similar to a bladder but materially 

 thinner, and filled with a liquid which 

 evidently affords nourishment to the 

 animal. Plate 1st, fig. 2d, C C. G 

 a piece of wood to which the peduncle 

 is affixed. 



