Sorth Pacijio Zoroasterida*. ;58U 



c'. Adrndial plntes present; two8ori«'9of 

 pajmlHr arcns hetwofii tli« cariiinl and 

 superomur^'iiml i)Iat».-.s, the latU>r ik-vit 

 conspiciioiiely eiilargi'd nor ovcrlajH 

 pinjr tilt' cariiials. (ienotyi»", Zoro- 

 aster sacciilnttig, Kisljer Myxodtnna ♦, i'isher 



c'. No adrndiul plate^t ; one Berios of very 

 email adradial papular pores ; supero- 

 niar^'inal plates of two sizi's, altor- 

 natoly larj^iT and MinalU'r, ovfrlap])in^ 

 the carinals strim^'ly and doininatin^,' 

 these platos, which are suiikt-n bolow 

 the It'Vt'l iif the superonmrfriiuils, 

 tu'notype, lii/thiolophus acanlhinus, 



Fisher Iiyth{ohphu$\, F.sher, 



a}. Abftcliinil plates of disk, the carinals, ad- 

 radials (when present), niarjrinals, and 

 sometimes one series of actinolateral plates 

 devoid of sj)ines or an-v conspicuous arma- 

 ture, but mostly smooth and covered with 

 a touj.'h meuibrane of variable thickness, 



often partly obscurinff the plates ; two to • 



four lower series of actinolateral plates 



covered with squamiform llesliy spinelets 



and sometimes a conspicuous ajjpressed 



spine; superambulacral plates present, the 



first conspicuously enlarjred into a buttress 



connecting: the upper end of the first two 



ambulacral ossicles with the body-wall. 



h' . With a series of adradial plates more or 



less well developed ; four or five series of 



actinolateral plates. (Jenotype, Cnemi- 



dafter ici/vi/lii, Sla len Cnemidnslvr \, Sladen. 



ft*. Adradial plates absent, the inner lobe of 

 the superoMiartjinal plates overlappin;; 

 the carinal i)late8 ; three series of actino- 

 lateral plates with rudimentary fourth 

 series in larfre specimens. (Jenotype, 

 Zoroaster siysberA, Perrier Muuuiiosttr, Perrier. 



Kei/ to the Xorth Pacific Specirs and Subspecies of Zoroaster. 



a'. Willi four series of actinolateral plates on 

 proximal part of ray ; dorsolateral and 

 iiitermar^nnal papular areaa very small 

 with normally one papida each ; infero- 

 marprinal and actinolateral spines slender, 

 closely apressed. 



• Mt/Todertna, Fisher (snbjrenus), Bull. Bureau Fisheries, 1904, 

 vol. xxu.. Jinie 10, 1905, p. .SIO. 



t Iii/t/ii"/<>j>hiis, Fisher, * New Ka.'^t Indian Starfishes,' Proc. Biol. Soc. 

 Washington, vol. xxix., Feb. I'l. 19I<>, p. ."il. 



X I have examined large adult specimens. Sladen's type was small, 

 very immature, and therefore had not developed some of tne charucters 

 of the adult. 



Auu. d; Ma.,. .V. 11 1st. Ser. 9. IV. iii. 2G 



