DITEEMATA. 67 



Goniaster (Agass.). Body thick, bordered by a 

 series of plates edged with spines ; avenues bor- 

 dered by transverse rows of spines. 



G. Templetoni. Fig. 102 ; \. G. equestris. 



Abbensis. 



Sub-Family IV. Asteriana. 

 Asterias (Linn.). Body star-shaped; rays flat, 

 with a border of marginal plates ; avenues bor- 

 dered by three sets of spines. 



A. aurantiaca. Fig. 103 ; -J-. 



Luidia (Forbes). Body star-shaped, many-rayed; 

 rays flat, covered above with spine-bearing warts ; 

 avenues bordered by two sets of spines. 

 L. fragilissima. Fig. 104 ; -fa. 



SUB-CLASS II. DITREMATA. 



Shell calcareous, forming a spherical or 

 disk-like shield, composed of immoveable 

 plates ; locomotion by suckers and spines. Echinoidea. 



No shell; but the leathery skin con- 

 taining calcareous reticulated pieces : gul- 

 let surrounded by a calcareous ring; 

 body cylindrical; locomotion usually by 

 suckers; mouth encircled by feathery 

 tentacles Holothuroidea. 



