40 POPULAR CONCHOLOGY. 



oval. Operculum consisting of four valves.* 

 Animal unknown. — 3 recent species. 

 Found in madrepores. 



Some modern writers have introduced into 

 this family several new genera, but as the dis- 

 tinctions are founded upon characteristics of 

 secondary importance, they will not be de- 

 scribed in these pages. 



Family 2. — Cirrhipeda pedunculata^ 



The body of the animals of this family is 

 supported by a tubular peduncle, flexible and 

 tough, the base of which is affixed to marine 

 substances. The shell is variable in form, but 

 always composed of several valves. — There are 

 6 genera. 



18. Lithotrya (Sowerby). — 

 Shell irregular in form, compressed 

 and pyramidal, consisting of eight 

 unequal pieces ; having at the base 

 an irregular cap-shaped appendage, 

 like the inverted shell of a Patella, 

 and to which the lower part of the 



* Some authors say only two. 

 \ Cirripedes Pedoncules, Lamarck. 



