30 CLASSIFICATION OF THE ANIMAL KINGDOM. 



(Miiller and Troschel, System der Asteriden, 1842 ; A. Agassiz, North 

 American Star-fishes, Cambridge, Mass., 1877 ; E. Perrier, Revision de la 

 Collection de Stellerides du Museum d'Histoire naturelle de Paris, Archiv de 

 Zool. Exper., 1876.) 



ORDER III. OPHIUROIDEA (Brittle-stars). 



Fam. a. Ophiuridse. Ophiura, Ophioglypha (fig. 26), 



OpJiiolepis, Ophiocoma. 

 Fam. &. Euryalidse. AsleropTiyton (Euryale), Aster onyx. 



(Lyman, Ophiuridce and Astrophytidce, Cat. of the Museum of Comp. 

 Zool. at Harvard, 1865 ; Lutken, Additamenta ad historiam Ophiuridarum, 

 1859 ; Ludwig, Morphologische Studien an Echinodermen, 1880.) 



Pig. 26. Ophiuroidea. Ophioglypha lacertosa : A, Outline, of the natural size ; B, The 

 disc viewed from above, twice the natural size ; c, The disc viewed from below, showing 

 the mouth and genital fissures, twice the natural size. (Original.) 



