1881.] PROF. F.J. BELL ON THE GENUS ASTERIAS. 505 



(ii.) TyiiacautluLla. 

 i. SimpHces. Dorsal spines arranged on the type of A. rubens. 

 A. amurensis. A. rvhens. 



A. ochotensis. A. vulgaris. 



ii. Rarispinosce. Dorsal spines rare (as in A. glacialis). 



A. alba. 



iii. Retusispinosce. Spines blunted and short. 

 A. epichlora. 



iv. Acutispinosa. Spines pointed and sharp. 

 A. cribraria. A. litloralis. 



A.japonica. A. tenera. 



ii. MONACANTHIDA. 



CI. ECHINOPLACIDA, 



0. 



ft. Anechinoplacida. 



(i.) Autacanthida. 



0. 



ii. Typacanthida. 

 i. SimpHces. 

 A. cunninghami. ? A. luetkeni. 



A. forbesi. 



ii. Rarispinosce. 

 A. ttfricana. A. rarispina. 



A. glacialis. A. webbiuna. 



A. paucispinn. (? A. Jissispina.) 



iii. Retusispinosae. 

 A. anlarctica. [? A. capitata. 



A. troscheli, ? A. conferta.'] 



iv. Acutispiuosse. 

 0. 



C. Polyacanthida. 



a. ECHINOPLACIDA. 



A. panopla. 



Mode of formulating Results. 



By the use of the following symbols one may see at a glance which 

 of these characters are possessed by any given species, by assinging 

 the following symbols to the different characters : — 



1 = monacanthid ; 2=:diplacanthid ; 3 = polyacanthid j 

 »i=mouoplacid ; jo=polyplacid ; 

 Proc. Zool. Soc— 1881, No. XXXIII. 33 



