28 



CLASSIFICATION OF THE ANIMAL KINGDOM. 



Sub-ord. 3. Irregularia. 



Fam. a. Echinoconidse. Pygaster, *Galerites. 



Fam. b. Clypeastridae. Clypeaster, EcMtwcyamus, Fibu- 



laria. 

 Fam. c. Scutellidse. Mellita, Rotula, Echinarachnius, 



Fam. d. Echinoneidse. Echinoneus. 



Fam. e. Echinobrissidae. Nudeolites. 



Fam. /. Echinolampadae (Cassidulidae). EcJiinolampas, 



Rhynclwpygus. 



Fam. g. *Collyritidse (Dysastridse). Colly rites. 

 Fam. h. *Ananchytidse. Ananchytes. 

 Fam. i. Spatangidse. Spatangus, Amphidetus, Brissus, 



*Micraster. 



(L. Agassiz, Monographic d'Echinodermes vivans et fossiles, 1838-42 ; A. 

 Agassiz, Revision of the Echini, 1874 ; Loven, Etudes sur les Echino'ides, 

 1874 ; A. Agassiz, Report on the Echinoidea, Report of the Scientific Re- 

 sults of the Exploring Voyage of H.M.S. Challenger, 1881.) 



Fig. 24. Echinoidea. Test of Echinus esculentus, viewed from above, a, One of the 

 ambulacral areas ; ia, One of the interambulacral areas. 



