REVISION OF PALEOZOIC STELLEROIDEA. 127 



ANORTHASTER MIAMIENSIS (Miller). 



Plate 13, fig. 4; plate 20, fig. 1. 



Palasaster miamiensis Miller, Journ. Cmcinnati Soc. Nat. Hist., vol. 3, 1880, 

 p. 143, pi. 4, fig. 3. 



Original description. — "Pentagonal; rays about one and a half 

 times the diameter of the body, or about nine- tenths of an inch; 

 diameter of the body about six-tenths of an inch; breadth of a ra}^ 

 at the point of junction with the body a Httle more than half the 

 diameter of the body, or about seven-twentieths of an inch; rays 

 obtusely pointed. 



"Marginal plates wider than long, and numbering about 12 in 

 the length of hah an inch from the body. Two marginal plates 

 form the junction of the rays. Ambulacral furrow wide, the plates 

 being more than twice as long as wide. There are about 18 ambu- 

 lacral plates in a length of one-half inch, and each one is provided 

 with an angular ridge tapering from the marginal plates to the furrow." 



Emended description. — R = 23 mm., r = 7 mm., R = 3.2r. Width of 

 rays at base 8 mm. 



Rays tapering very slowly in the proximal hah, but more rapidly 

 distally. 



Abactinal area unknown. 



Inframarginal plates about 16 in each column and subquadrangular 

 in outUne. These ossicles do not continue into the axils, but rest 

 upon the second large axillary adambulacral plate. 



Adambulacral plates about 18 in each column, like the infra- 

 marginal pieces, increasing in size proximally, while the two axillary 

 ones are suddenly enlarged, extend to the margin of the disk, and have 

 the position of marginal ossicles. Orally to the latter the adambu- 

 lacral plates continue as interbrachial ossicles. The distal pair is 

 large and both are wedge-shaped, followed by two pairs of quite 

 small quadrangular plates and a final pair of long and narrow plates; 

 in all there arc, therefore, 22 adambulacral plates in each column. 

 The interbrachial adambulacral plates are terminated by a single 

 quadrangular oral plate wedged in between the proximal ambu- 

 lacrals. 



iVmbulacral furrows very wide, broadly gutter-shaped. Ambu- 

 lacral plates about 30 in a column, slightly alternating, decidedly 

 wider than long proximally, increasing in length distally, and finally 

 becoming about as wide as long near the apex of a ray. Each plate 

 is slightly carinated, the ridges crossing the plates from the lateral 

 distal edge to the medial proximal edge. The proximal ambulacral 

 plates are modified, conspicuous, and subtriangular in outhne. 

 Podial openings between two adjoining plates in alternate sutures at 



50601°— Bull. 88—15 9 



