ASTEROIDKA OF NORTH PACIFIC AND .VDJACENT WATERS FISHER. 



39 



althou<^h the last is exceedinf^ly close to Sideriaster, which Vernll (1899) consitlers 

 an undoubted astropectinid. 



Table of genera of Aslropeclinidx detailing their characters, but not including family characteristics. {The 

 three marked with an asterisk Itave not been examined by the writer.) 



a Furrow spines comparatively few, in an angular or curved comb Intermediate between tiie two types. 



d Shallow. 



c Lobf^d, imbricating, convex plates simulating tabulate paxilla? (perhaps pseudopaxillie). 



dNot always. 



e Also protbpaxilljp. 



/A special type, derived from the astropectinid. 



KEY TO THE KNOWN f:ENER.\ OF .\STROPECTINID^. 



a'. No specialized spines on either series of marginal plates; marginals armed with a uniform covering 

 of small papilliform or squamiform spinelets. 

 6'. Superomarginals smaller than inferomarginals. 



c'. Furrow margin of adambiilacral plates angular, short, with a series of few long delicate spine- 

 lets. Madreporic body small, often partly hidden, but without special paxilte on its sur- 

 face; odd interradial actinal intermediate plates Leptyrhastcr" Smith, p. 42. 



c'. Furrow margin of adambiilacral plates gently curved, long (plate conspicuously longer than 

 wide), bearing about S short spinelets. Madreporic body large, covered with special 



paxillse; no odd interradial actinal intermediate plates Lonchotastcr b Sladcn. 



6^. Superomarginals not conspicuously smaller than inferomarginals; both series high, confined to side 

 of ray; incipient marginal spinulcs in one superomarginal series, and two inferomarginal longi- 

 tudinal series Sathybiaster c Danielssen and Keren. 



a Includes Paraslropecten Ludwig and Glyphaster Verrill. 



6 Refers to Lonchotastcr forcipifer; see sections a', 5', c'. rf*. 



" Bathybiaster robiislus frequently has the marginal spinules very small. 



