612 PROCEEDINGS OF THE NATIONAL MUSEUM. voh.4[i. 



Type-locality. — Station 5289, Verde Island Passage, north of 

 Mndoro (lat. 13° 41' 50" N.; long. 120° 58' 30" E.), 172 fathoms, 

 broken shells, sand. 



Astromesites differs from Persephonaster, Psilaster, and Bathy- 

 hiaster in having an odd interradial series of actinal intermedial (> 

 plates. It differs further from Persephonaster in lacking the latter's 

 characteristic angular marginal series (or fasciculate group) of oral 

 spines, and in having an angular series of furrow spines, rather than 

 a comb; from Psilaster in having broader mouth plates \vith numer- 

 ous, crowded suboral spines in more than 1 series, an angular (not 

 pectinate) furrow armature, and in lacking the thick, fleshy, actinal 

 spinelets; from Batkyhiaster in lacking lobes on the abactinal plates, 

 fleshy actinal spinelets, and in having a different type of dental 

 and marginal armature. Astromesites agrees with Blakiaster and 

 Lcptychaster in having the odd interradial series of actinal inter- 

 mediate plates, and the same t}^)e of adambulacral armature. It 

 differs from BlaMaster, however, as indicated in the diagnosis, and 

 from Leptycliaster in having armed inferomarginals of the type of 

 Psilaster and Persephonaster. I should be inclined to rank Astrome- 

 sites with BlaJciaster were not the abactinal plates wholly different. 



Genus PERSEPHONASTER Alcock. 



KEY TO THE SPECIES OF PERSEPHONASTER HEREIN DESCRIBED. 



a\ Marginal plates broad and conspicuous, the inferomarginals fonning a wide bevel 



to actinal surface and bearing, on the outer tumid end, which projects laterally 



beyond superomarginals, a prominent comb of slender spines, covering, at 



least proximally, a second smaller parallel comb; superomarginals with a 



transverse series of appressed spines or spinules. 



6^. With several spines on the actinal surface of inferomarginals in addition to the 



lateral comb. 



c^ Rays broad and petaloid, abruptly narrowed to a very attenuate extremity; 



paxillar area broad; actinal intermediate plates extending fully two-thii-ds 



the length of ray, and larger; inferomarginal plates wider; superomarginal 



spines more prominent and numerous euryactis. 



(?. Rays narrower, evenly tapered; paxillar area narrower; actinal intermediate 

 plates extending a little over one-half length of ray, and very small distally; 

 inferomarginals narrower; superomarginal spinulesi nconspicuous. 



luzonicus. 



V. Only the lateral comb of inferomarginal spines (except on fast 3 or 4 plate.s). 



anchistiis. 



0?. Marginal plates massive, but not especially broad, tlie side of ray vertical; rays 

 slender, more or less attenuate at tip; second lateral comb obsolete; supero- 

 marginals unarmed or with single spine, not a transverse series. 

 6^ Superomarginals not conspicuously tumid and without special spine; no abac- 

 tinal pedicellarise independent of paxillse tenuis. 



b'K Superomarginals tumid, with a single spine, forming a straight series along ray; 

 among the paxillse low plates bearing fasciculate pedicellarise independent 

 of paxillte; no erect lateral spine above the inferomarginal comb. 



