300 INVERTEBRATE FAUNA OF SOUTH CAROLINA. 



ORDER ECHNOIDExV. SEA URCHINS. 



[Echinoderms with a shell usually globose in shape, and made up of calcareous 

 plates, having a definite arrangement. Teeth present, forming a complicated mechan- 

 ism, known as Ari.stotle's lantern, Pedicellaria present in some ] 



Arbacia punctulata Gray (N. C.) 



(Commonly known as the purple sea-urchin). 

 Cidaris tribuloides Bl. 

 Clypeaster subdepressus Ag. 

 Echinanthus rosaceus Gray. 

 Echinometra subangularis Desml. 



Echinocardium flavescens A. Ag. Echinocardium cordatum Gray. 



Encope emarginata Ag. 

 Mellita pentapora Liitken | Sand cakes. 



sexforis A. Ag. j Shape flattened. 



Moira atropos A. Ag. 

 Strongylocentrotus droebachiensis A. Ag. 



(Commonly known as the green sea-urchin). 

 Toxopneustes variegatus A. Ag. (X. C.) 



ORDER ASTROIDEA. STAR-FISHES. 



[The viscera extending into each of the five arms. Pedicellaria present. No teeth.] 



Asterias forbesii Verrill (X. C.) Asterias spinosus Link. 



Astropecten articulatus (Say) Luetken. 

 Luidia clathatra (Say) Luetken. 



ORDER OPHIUROIDEA. BRITTLE SEA-STARS. 



[Body discoidal ; the five arms do not contain prolongations of the alimentary canal- 

 No pedicellaria. A masticatory apparatus.] 



Ophiura brevispina Say. Ophiura elongata Say. 



Ophiophragmus wurdemanni Lyman (N. C.) 

 Ophiotrix angulata Ayres. 



