REPORT ON TUE ASTEROIDEA. 193 



Madreporiform body large, a little more than its own diameter distant from the 

 marsrin. 



Remarks. — The genus Moiraster is established for the reception of a well-characterised 

 form described by Professor Jeffrey Bell 1 under the name of Archaster magnijicus, the 

 types of which are in the British Museum. 



Through the kindness of Professor Bell I have had every facility for examining this 

 interesting starfish. Judging from the superficial examination of the dried examples I 

 consider that the character of the abactinal plating, the form of the marginal plates, the 

 extensive development of the interradial areas, the character of the intermediate plates, 

 and the presence of the strongly-developed superambulacral plates of Archaster magnijicus 

 necessitate its separation from Archaster as now defined. I have also great doubts as to 

 the presence of an anal orifice. I regard the form as the type of a distinct genus, for 

 which, at the request of my friend, I have proposed a name, in order that it might be 

 placed in the foregoing synopsis. The natural position of Moiraster appears to be inter- 

 mediate between Leptoptychaster and Astropecten. 



Supplementary to the excellent specific description given by Professor Bell, I have 

 added the preceding notes "on the characters which may be taken as diagnostic of the 



1. Moiraster magnijicus, Bell, sp. 



Archaster magnijicus, Bell, 1881, Ann. and Mag. Nat. Hist, ser. 5, vol. viii. p. 440. 



Locality. — St Helena. Collected by Mr J. C. Melliss. 



No example of this form was obtained by the Challenger Expedition. 



Genus Astropecten, Linck. 



Astropecten, Liuck, De Stellis marinis, 1733, p. 26. 

 Stellaria, Nardo, De Asteriis, Oken's Isis, 1834, p. 716. 

 Asterias, Agassiz, Mem. Soc. Sci. Nat. Neuchatel, 1835, t. i. p. 168. 

 Crenaster, d'Orbigny, Prodrome de Pal^ontologie, 1850, t. i. p. 240. 



This genus is world-wide in its distribution, but confined to the temperate and tro- 

 pical regions. Nearly all the species inhabit shallow water, and, with the exception of 

 three, are confiued to the Littoral zone. 



The number of species is large, and the morphological plasticity of the genus consider- 

 able, as might naturally be expected in a type extended over such a wide area ; the 

 species maintaining, however, the type facies in a remarkable manner. 



1 Ann. a?id Mag. Nat. Hist., 1881, ser. 5, vol. viii p. 440. 



(ZOOL. CHALU EXP. — PART LI. — 1888.) 25 



