NO. 1673. RECENT CRINOIDS FROM THE PHILIPPINES— CLARK. 405 



plating on brachial and pinnule ambulacra very highly developed; 

 perisome of the arms completely covered with rather large inter- 

 brachial plates, so that the arms and pinnules, when the covering 

 plates are closed, are completely encased in a calcareous covering. 



Ends of the basal rays visible as small, though prominent, tuber- 

 cles in the angles of the calyx; radials of uniform width all around 

 the calyx, short, somewhat over four times as broad as long, the 

 anterior edge set with small scattered spines; I Br^ short, of uniform 

 height, the posterior border convex, the anterior concave, about three 

 times as broad as long, the posterior edge slightly prominent, the lat- 

 eral edges in very close apposition, and rather prominently everted, 

 the crest of the resultant ridge finely spinous; I Br^ broadly 

 pentagonal, the lateral edges about as long as those of the I Br^, about 

 twice as broad as long, the lateral edges everted and finely spinous 

 like those of the I Br^ ; like the I Br^ and the first two brachials it 

 bears a single small rather prominent rounded tubercle near each 

 lateral margin. 



Arms ten, stout and rugged, gradually becoming slender distally, 

 150 mm. long; first brachial longer exteriorly than interiorly, concave 

 anteriorly, the interior edges closely united, the exterior in close 

 apposition, everted and spinous like those of the preceding joints; 

 second brachial about twice as large, irregular in shape, strongly 

 convex posteriorly, in close apposition and strongly flattened with 

 everted and spinous edges, both exteriorly and interiorly; third and 

 fourth brachials (syzygial pair) half again as broad as long, flat- 

 tened exteriorly and interiorly, the edges less everted than those of 

 the preceding joints; following five brachials approximately oblong, 

 rather strongly tubercular, about three times as broad as long, after 

 the twelfth becoming triangular, about as long as broad, this propor- 

 tion remaining unchanged until near the arm tips, where the brach- 

 ials become wedge-shaped, and somewhat longer; the distal edges 

 of the brachials in the outer two-thirds of the arm are overlapping 

 and finely spinous. Syzygies occur between the third and fourth 

 brachials, again between the fourteenth-fifteenth to seventeenth- 

 eighteenth, and distally at intervals of four to ten (usually six or 

 seven) oblique muscular articulations. 



Pi large and very stout, strongly flattened exteriorly, with seven- 

 teen or eighteen joints all broader than long; the pinnule tapers 

 rather rapidly after the proximal third, so that the terminal portion 

 is delicate, with very small joints; Po 7 mm. long, stout basally, 

 though not nearly so stout as P j, tapering rapidly, so that the distal 

 half is slender; it is composed of fourteen joints, the first three 

 broad, the fourth about as long as broad, the remainder somewhat 

 longer than broad; the first six joints of P^ have the distal side very 

 strongly concave, forming two sharp keels, one external along the 



