14 



COPK 



Class I.— AGNATHA. 



The known members of the class Agnatha are a very 

 small representation of those that once existed; and they 

 present a great variety of characters, having little affinity 

 with each other. Three subclasses are most distinctly in- 

 dicated : 

 An osseous dermal skeleton with lateral 



limb-like appendages; Ostracophori. 



An osseous axial skeleton; no dermal 



skeleton; ? appendages; Cydias. 



