SECTION XIL 249 



Some kinds of Spondyles are thickl j and 

 curioufly iet with long thorns or fpikes ; 

 thefe are generally, and very erroneoufly, 

 called Thorny Oyjlers, and, when perfeft, 

 are greatly valued. PI. VI. fig. 4, 



This family is not very numerous in its 

 fpecies. 



Lifter, Woodward, Gualtieri, Linnseus, 

 and Meufchen, all rank them as a particular 

 genus, by the name of Spondylus ; but 

 Rumphius, Argenville, Seba, and Davila, 

 rank them very erroneoufly as Oyfters. 



The third family is the Oftreum or 

 Oyfter. The Oyfters have unequal valves, 

 though there are fome fpecies that have 

 equal valves, but none are eared. The 

 hinge of this family has not any teeth, 

 but confifts of one large inarticulate gut- 

 ter running the length of the top of the 

 Sfiell, in both Shells alike, and is covered 



and 



