A NEW SEA STAR FROM JAPAN FISHER 



471 



In this species, from Arooiitina, the spinelets are larger and thicker, 

 the length being 2.5 times the thickness, while the thorns are rela- 

 tively smaller (de Loriol, 1904, pi. 3, fig. 1^). 



The convex madreporite is 4.5 mm on the interradial (longer) 

 diameter, is guarded by 4 spines, and its inner border is at the middle 

 o^ r. 



d 



a b c 



Figure 56. — Poramo^isis japonica, new sj>ecies : a, Deiuial spinelet from abactiiiul papular 

 area, X 100 ; b, outer of the two ailambulacral spines, with Its slieath, or saceulus, 

 showing the outer face or that away iiom the ambulacral furrow, x 10 ; c, same spine 

 as h, with sheath removed, X 10 ; d. tifth and sixth adambulacral plates and spines 

 viewed from furrow and showing the sides opposite to b, X 5. 



The broad intermarginal papular areas, 12 to a side, are actlnal in 

 position, becoming lateral sometimes at end of ray. The proximal 

 areas contain the dermal spinelets. Interradially, the distance be- 

 tween the first sujieromarginal and corresponding inferomarginal 

 spines is one-third r. Superomarginal spines 13, spaced about their 

 own length. The proximal 1 to 5 inferomarginal plates carry a 

 single spine, the others 2 spines except for 1 or 2 triplacanthed plate^i 

 at midray and a sporadic monacanthed plate near the end; 15 plates 

 in all. The sui>eromarginal spines taper from a broad base to a 

 rather slender blunt point. The inferomarginal s are similar, al- 

 though the tip is sometimes compressed, rounded or incipiently bifid 

 but not markedly channeled. Intermarginal spines at base of ray 

 for the 10 areas are : 1, 1, 0, 1, 0, 2, 0, 1, 1. 2. 



Actinal interradial areas with 20 to 23 prominent spines, there 

 l>eing a well-defined arcuate series similar and parallel to the inferu- 

 marginals, the outermost spinelet at about utiddle of ray measured 

 on side. Inside of this an incomplete second series is indicated, 

 which in number and arrangement is not materially diifei-ent from 



