REVISION OF PALEOZOIC STELLEEOI0EA. 245 



made impressions. Na specimen gives any clue to the dorsal exterior 

 save one arm which has been turned sidewise showing a part of that 

 surface. 



"The striking character of this starfish is the unusual delicacy of 

 its arms, which are very slender and long for a true asteroid and 

 present an appearance very suggestive of an ophiuran. These slender 

 arms are usually so exposed as to show only the alternating am- 

 bulacral plates which increases the effect of slenderness; but the 

 adambulacrals are occasionally present and give the arms increased 

 width. These arms are all clearly sulcate, the median groove being 

 sharply marked in all casts by a thin elevated ridge running the 

 entire length of the arm. The soft shale holding these specimens is 

 not a very satisfactory matrix from which to take the special struc- 

 tures of the animal but in good part these can be made out. The 

 ambulacral plates are quadrate in outline, alternate in position along 

 the arm groove, and together are arched so that normally the am- 

 bulacral surface is an arched ridge rising above the rest of the surface. 

 These plates, in their arched position, are slightly spaced or dis- 

 placed along adjoining edges leaving passages from the ambulacra. 

 They are usually broken down or slipped over each other in com- 

 pression so that the arm seldom* shows them in the true position. 

 The surface of these plates is finely granular. The adambulacrals 

 constitute one (or more ?) lateral rows and are so seldom well defined 

 that I am not able to represent them with precision but each of them 

 seems to carry one short spine and all to be granulated on the surface. 

 The body of the animal is deeply incut by the arms, which radiate 

 from a narrow center, sharply quinquepartite by the buccal cavity. 

 The oral apparatus is pretty well made out. The oral frames, one 

 for each arm, are very conspicuous, though varying in size in different 

 individuals. Each is broadly saddle-shaped, split medially, the distal 

 parts joined by a suture, the proximal ends spreading apart at a 

 sharp angle which opens into the oral cavity. Their surface is 

 rounded and granulate, the distal ends elevated, and often each half 

 is inclined downward toward the other along the median suture. 

 At each proximal angle lies a sharp jaw or tooth. The whole of the 

 body surface is occupied by the oral rosette composed of the five 

 Jbuccal divisions." 



Formation and locality. From the Devonic of Ponta Grossa and 

 Jaguariahyva, Brazil. 



ENCRINASTER (?) GRAY^E (Spencer). 



Aspidosoma grayse. SPENCER, Mon. Brit. Pal. Asterozoa, pt. 1 (Palseontogr. Soc. 

 for 1913), 1914, pp. 23, 24, 33, 38, text figs. 22, 24, pi. 1, fig. 8. 



Occurs in the Caradoc of Great Britain. 



